Charged particle cancer therapy beam path control method and apparatus

ABSTRACT

The invention comprises a charged particle beam path coupling an injector, synchrotron accelerator, beam transport system, targeting system, and/or patient interface method and apparatus. Preferably, the injector comprises: a negative ion beam source, a two phase ion source vacuum system, an ion beam focusing lens, and/or a tandem accelerator. Preferably, the synchrotron comprises turning magnets, edge focusing magnets, magnetic field concentration magnets, winding and correction coils, flat magnetic field incident surfaces, and/or extraction elements. Preferably, the synchrotron, beam transport system, targeting system, and patient interface combine to allow multi-axis/multi-field irradiation, where multi-axis control comprises control of horizontal and vertical beam position, beam energy, and/or beam intensity and multi-field control comprises control of patient rotation and distribution of delivered energy in and about the tumor in a time controlled, targeted, accurate, precise, dosage controlled, and/or efficient manner.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application:

-   -   is a continuation-in-part of U.S. patent application Ser. No.        12/425,683 filed Apr. 17, 2009, which claims the benefit of:        -   U.S. provisional patent application No. 61/055,395 filed May            22, 2008;        -   U.S. provisional patent application No. 61/137,574 filed            Aug. 1, 2008;        -   U.S. provisional patent application No. 61/192,245 filed            Sep. 17, 2008;        -   U.S. provisional patent application No. 61/055,409 filed May            22, 2008;        -   U.S. provisional patent application No. 61/203,308 filed            Dec. 22, 2008;        -   U.S. provisional patent application No. 61/188,407 filed            Aug. 11, 2008;        -   U.S. provisional patent application No. 61/188,406 filed            Aug. 11, 2008;        -   U.S. provisional patent application No. 61/189,815 filed            Aug. 25, 2008;        -   U.S. provisional patent application No. 61/201,731 filed            Dec. 15, 2008;        -   U.S. provisional patent application No. 61/205,362 filed            Jan. 12, 2009;        -   U.S. provisional patent application No. 61/134,717 filed            Jul. 14, 2008;        -   U.S. provisional patent application No. 61/134,707 filed            Jul. 14, 2008;        -   U.S. provisional patent application No. 61/201,732 filed            Dec. 15, 2008;        -   U.S. provisional patent application No. 61/198,509 filed            Nov. 7, 2008;        -   U.S. provisional patent application No. 61/134,718 filed            Jul. 14, 2008;        -   U.S. provisional patent application No. 61/190,613 filed            Sep. 2, 2008;        -   U.S. provisional patent application No. 61/191,043 filed            Sep. 8, 2008;        -   U.S. provisional patent application No. 61/192,237 filed            Sep. 17, 2008;        -   U.S. provisional patent application No. 61/201,728 filed            Dec. 15, 2008;        -   U.S. provisional patent application No. 61/190,546 filed            Sep. 2, 2008;        -   U.S. provisional patent application No. 61/189,017 filed            Aug. 15, 2008;        -   U.S. provisional patent application No. 61/198,248 filed            Nov. 5, 2008;        -   U.S. provisional patent application No. 61/198,508 filed            Nov. 7, 2008;        -   U.S. provisional patent application No. 61/197,971 filed            Nov. 3, 2008;        -   U.S. provisional patent application No. 61/199,405 filed            Nov. 17, 2008;        -   U.S. provisional patent application No. 61/199,403 filed            Nov. 17, 2008; and        -   U.S. provisional patent application No. 61/199,404 filed            Nov. 17, 2008;    -   is a continuation-in-part of U.S. patent application Ser. No.        12/687,387 filed Jan. 14, 2010, which        -   is a continuation-in-part of U.S. patent application Ser.            No. 12/425,683 filed Apr. 17, 2009;        -   claims the benefit of U.S. provisional patent application            No. 61/209,529 filed Mar. 9, 2009;        -   claims the benefit of U.S. provisional patent application            No. 61/208,182 filed Feb. 23, 2009;        -   claims the benefit of U.S. provisional patent application            No. 61/208,971 filed Mar. 3, 2009; and        -   claims the benefit of U.S. provisional patent application            No. 61/270,298, filed Jul. 7, 2009; and    -   claims the benefit of U.S. provisional patent application No.        61/308,621, filed Feb. 26, 2010,    -   all of which are incorporated herein in their entirety by this        reference thereto.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to treatment of solid cancers. Moreparticularly, the invention relates to a charged particle cancer therapymethod and apparatus.

2. Discussion of the Prior Art

Cancer

A tumor is an abnormal mass of tissue. Tumors are either benign ormalignant. A benign tumor grows locally, but does not spread to otherparts of the body. Benign tumors cause problems because of their spread,as they press and displace normal tissues. Benign tumors are dangerousin confined places such as the skull. A malignant tumor is capable ofinvading other regions of the body. Metastasis is cancer spreading byinvading normal tissue and spreading to distant tissues.

Cancer Treatment

Several distinct forms of radiation therapy exist for cancer treatmentincluding: brachytherapy, traditional electromagnetic X-ray therapy, andproton therapy. Proton therapy systems typically include: a beamgenerator, an accelerator, and a beam transport system to move theresulting accelerated protons to a plurality of treatment rooms wherethe protons are delivered to a tumor in a patient's body.

Proton therapy works by aiming energetic ionizing particles, such asprotons accelerated with a particle accelerator, onto a target tumor.These particles damage the DNA of cells, ultimately causing their death.Cancerous cells, because of their high rate of division and theirreduced ability to repair damaged DNA, are particularly vulnerable toattack on their DNA.

Charged Particle Cancer Therapy

Patents related to the current invention are summarized here.

Proton Beam Therapy System

F. Cole, et. al. of Loma Linda University Medical Center “Multi-StationProton Beam Therapy System”, U.S. Pat. No. 4,870,287 (Sep. 26, 1989)describe a proton beam therapy system for selectively generating andtransporting proton beams from a single proton source and accelerator toa selected treatment room of a plurality of patient treatment rooms.

Accelerator/Synchrotron

S. Peggs, et. al. “Rapid Cycling Medical Synchrotron and Beam DeliverySystem”, U.S. Pat. No. 7,432,516 (Oct. 7, 2008) describe a synchrotronhaving combined function magnets and a radio frequency (RF) cavityaccelerator. The combined function magnets function to first bend theparticle beam along an orbital path and second focus the particle beam.The RF cavity accelerator is a ferrite loaded cavity adapted for highspeed frequency swings for rapid cycling particle acceleration.

H. Tanaka, et. al. “Charged Particle Accelerator”, U.S. Pat. No.7,259,529 (Aug. 21, 2007) describe a charged particle accelerator havinga two period acceleration process with a fixed magnetic field applied inthe first period and a timed second acceleration period to providecompact and high power acceleration of the charged particles.

T. Haberer, et. al. “Ion Beam Therapy System and a Method for Operatingthe System”, U.S. Pat. No. 6,683,318 (Jan. 27, 2004) describe an ionbeam therapy system and method for operating the system. The ion beamsystem uses a gantry that has a vertical deflection system and ahorizontal deflection system positioned before a last bending magnetthat result in a parallel scanning mode resulting from an edge focusingeffect.

V. Kulish, et. al. “Inductional Undulative EH-Accelerator”, U.S. Pat.No. 6,433,494 (Aug. 13, 2002) describe an inductive undulativeEH-accelerator for acceleration of beams of charged particles. Thedevice consists of an electromagnet undulation system, whose drivingsystem for electromagnets is made in the form of a radio-frequency (RF)oscillator operating in the frequency range from about 100 KHz to 10GHz.

K. Saito, et. al. “Radio-Frequency Accelerating System and Ring TypeAccelerator Provided with the Same”, U.S. Pat. No. 5,917,293 (Jun. 29,1999) describe a radio-frequency accelerating system having a loopantenna coupled to a magnetic core group and impedance adjusting meansconnected to the loop antenna. A relatively low voltage is applied tothe impedance adjusting means allowing small construction of theadjusting means.

J. Hirota, et. al. “Ion Beam Accelerating Device Having SeparatelyExcited Magnetic Cores”, U.S. Pat. No. 5,661,366 (Aug. 26, 1997)describe an ion beam accelerating device having a plurality of highfrequency magnetic field inducing units and magnetic cores.

J. Hirota, et. al. “Acceleration Device for Charged Particles”, U.S.Pat. No. 5,168,241 (Dec. 1, 1992) describe an acceleration cavity havinga high frequency power source and a looped conductor operating under acontrol that combine to control a coupling constant and/or de-tuningallowing transmission of power more efficiently to the particles.

Extraction

T. Nakanishi, et. al. “Method of Operating the Particle Beam RadiationTherapy System”, U.S. Pat. No. 7,122,978 (Oct. 17, 2006) describe acharged particle beam accelerator having an RF-KO unit for increasingamplitude of betatron oscillation of a charged particle beam within astable region of resonance and an extraction quadrupole electromagnetunit for varying a stable region of resonance. The RF-KO unit isoperated within a frequency range in which the circulating beam does notgo beyond a boundary of stable region of resonance and the extractionquadrupole electromagnet is operated with timing required for beamextraction.

T. Haberer, et. al. “Method and Device for Controlling a Beam ExtractionRaster Scan Irradiation Device for Heavy Ions or Protons”, U.S. Pat. No.7,091,478 (Aug. 15, 2006) describe a method for controlling beamextraction in terms of beam energy, beam focusing, and beam intensityfor every accelerator cycle.

K. Hiramoto, et. al. “Accelerator and Medical System and OperatingMethod of the Same”, U.S. Pat. No. 6,472,834 (Oct. 29, 2002) describe acyclic type accelerator having a deflection electromagnet and four-poleelectromagnets for making a charged particle beam circulate, amulti-pole electromagnet for generating a stability limit of resonanceof betatron oscillation, and a high frequency source for applying a highfrequency electromagnetic field to the beam to move the beam to theoutside of the stability limit. The high frequency source generates asum signal of a plurality of alternating current (AC) signals of whichthe instantaneous frequencies change with respect to time, and of whichthe average values of the instantaneous frequencies with respect to timeare different. The system applies the sum signal via electrodes to thebeam.

K. Hiramoto, et. al. “Synchrotron Type Accelerator and Medical TreatmentSystem Employing the Same”, U.S. Pat. No. 6,087,670 (Jul. 11, 2000) andK. Hiramoto, et. al. “Synchrotron Type Accelerator and Medical TreatmentSystem Employing the Same”, U.S. Pat. No. 6,008,499 (Dec. 28, 1999)describe a synchrotron accelerator having a high frequency applying unitarranged on a circulating orbit for applying a high frequencyelectromagnetic field to a charged particle beam circulating and forincreasing amplitude of betatron oscillation of the particle beam to alevel above a stability limit of resonance. Additionally, for beamejection, four-pole divergence electromagnets are arranged: (1)downstream with respect to a first deflector; (2) upstream with respectto a deflecting electromagnet; (3) downstream with respect to thedeflecting electromagnet; and (4) and upstream with respect to a seconddeflector.

K. Hiramoto, et. al. “Circular Accelerator and Method and Apparatus forExtracting Charged-Particle Beam in Circular Accelerator”, U.S. Pat. No.5,363,008 (Nov. 8, 1994) describe a circular accelerator for extractinga charged-particle beam that is arranged to: (1) increase displacementof a beam by the effect of betatron oscillation resonance; (2) toincrease the betatron oscillation amplitude of the particles, which havean initial betatron oscillation within a stability limit for resonance;and (3) to exceed the resonance stability limit thereby extracting theparticles exceeding the stability limit of the resonance.

K. Hiramoto, et. al. “Method of Extracting Charged Particles fromAccelerator, and Accelerator Capable Carrying Out the Method, byShifting Particle Orbit”, U.S. Pat. No. 5,285,166 (Feb. 8, 1994)describe a method of extracting a charged particle beam. An equilibriumorbit of charged particles maintained by a bending magnet and magnetshaving multipole components greater than sextuple components is shiftedby a constituent element of the accelerator other than these magnets tochange the tune of the charged particles.

Beam Energy/Intensity

M. Yanagisawa, et. al. “Charged Particle Therapy System, RangeModulation Wheel Device, and Method of Installing Range Modulation WheelDevice”, U.S. Pat. No. 7,355,189 (Apr. 8, 2008) and Yanagisawa, et. al.“Charged Particle Therapy System, Range Modulation Wheel Device, andMethod of Installing Range Modulation Wheel Device”, U.S. Pat. No.7,053,389 (May 30, 2008) both describe a particle therapy system havinga range modulation wheel. The ion beam passes through the rangemodulation wheel resulting in a plurality of energy levels correspondingto a plurality of stepped thicknesses of the range modulation wheel.

M. Yanagisawa, et. al. “Particle Beam Irradiation System and Method ofAdjusting Irradiation Apparatus”, U.S. Pat. No. 7,297,967 (Nov. 20,2007); M. Yanagisawa, et. al. “Particle Beam Irradiation System andMethod of Adjusting Irradiation Apparatus”, U.S. Pat. No. 7,071,479(Jul. 4, 2006); M. Yanagisawa, et. al. “Particle Beam Irradiation Systemand Method of Adjusting Irradiation Apparatus”, U.S. Pat. No. 7,026,636(Apr. 11, 2006); and M. Yanagisawa, et. al. “Particle Beam IrradiationSystem and Method of Adjusting Irradiation Apparatus”, U.S. Pat. No.6,777,700 (Aug. 17, 2004) all describe a scattering device, a rangeadjustment device, and a peak spreading device. The scattering deviceand range adjustment device are combined together and are moved along abeam axis. The spreading device is independently moved along the axis toadjust the degree of ion beam scattering. The combined device increasesthe degree of uniformity of radiation dose distribution to diseasedtissue.

A. Sliski, et. al. “Programmable Particle Scatterer for RadiationTherapy Beam Formation”, U.S. Pat. No. 7,208,748 (Apr. 24, 2007)describe a programmable pathlength of a fluid disposed into a particlebeam to modulate scattering angle and beam range in a predeterminedmanner. The charged particle beam scatterer/range modulator comprises afluid reservoir having opposing walls in a particle beam path and adrive to adjust the distance between the walls of the fluid reservoirunder control of a programmable controller to create a predeterminedspread out Bragg peak at a predetermined depth in a tissue. The beamscattering and modulation is continuously and dynamically adjustedduring treatment of a tumor to deposit a dose in a targetedpredetermined three dimensional volume.

M. Tadokoro, et. al. “Particle Therapy System”, U.S. Pat. No. 7,247,869(Jul. 24, 2007) and U.S. Pat. No. 7,154,108 (Dec. 26, 2006) eachdescribe a particle therapy system capable of measuring energy of acharged particle beam during irradiation of cancerous tissue. The systemincludes a beam passage between a pair of collimators, an energydetector, and a signal processing unit.

G. Kraft, et. al. “Ion Beam Scanner System and Operating Method”, U.S.Pat. No. 6,891,177 (May 10, 2005) describe an ion beam scanning systemhaving a mechanical alignment system for the target volume to be scannedallowing for depth modulation of the ion beam by means of a linear motorand transverse displacement of energy absorption means resulting indepth-staggered scanning of volume elements of a target volume.

G. Hartmann, et. al. “Method for Operating an Ion Beam Therapy System byMonitoring the Distribution of the Radiation Dose”, U.S. Pat. No.6,736,831 (May 18, 2004) describe a method for operation of an ion beamtherapy system having a grid scanner that irradiates and scans an areasurrounding an isocentre. Both the depth dose distribution and thetransverse dose distribution of the grid scanner device at variouspositions in the region of the isocentre are measured and evaluated.

Y. Jongen “Method for Treating a Target Volume with a Particle Beam andDevice Implementing Same”, U.S. Pat. No. 6,717,162 (Apr. 6, 2004)describes a method of producing from a particle beam a narrow spotdirected toward a target volume, characterized in that the spot sweepingspeed and particle beam intensity are simultaneously varied.

G. Kraft, et. al. “Device for Irradiating a Tumor Tissue”, U.S. Pat. No.6,710,362 (Mar. 23, 2004) describe a method and apparatus of irradiatinga tumor tissue, where the apparatus has an electromagnetically drivenion-braking device in the proton beam path for depth-wise adaptation ofthe proton beam that adjusts both the ion beam direction and ion beamrange.

K. Matsuda, et. al. “Charged Particle Beam Irradiation Apparatus”, U.S.Pat. No. 6,617,598 (Sep. 9, 2003) describe a charged particle beamirradiation apparatus that increases the width in a depth direction of aBragg peak by passing the Bragg peak through an enlarging devicecontaining three ion beam components having different energies producedaccording to the difference between passed positions of each of thefilter elements.

H. Stelzer, et. al. “Ionization Chamber for Ion Beams and Method forMonitoring the Intensity of an Ion Beam”, U.S. Pat. No. 6,437,513 (Aug.20, 2002) describe an ionization chamber for ion beams and a method ofmonitoring the intensity of an ion therapy beam. The ionization chamberincludes a chamber housing, a beam inlet window, a beam outlet windowand a chamber volume filled with counting gas.

H. Akiyama, et. al. “Charged-Particle Beam Irradiation Method andSystem”, U.S. Pat. No. 6,433,349 (Aug. 13, 2002) and H. Akiyama, et. al.“Charged-Particle Beam Irradiation Method and System”, U.S. Pat. No.6,265,837 (Jul. 24, 2001) both describe a charged particle beamirradiation system that includes a changer for changing energy of theparticle and an intensity controller for controlling an intensity of thecharged-particle beam.

Y. Pu “Charged Particle Beam Irradiation Apparatus and Method ofIrradiation with Charged Particle Beam”, U.S. Pat. No. 6,034,377 (Mar.7, 2000) describes a charged particle beam irradiation apparatus havingan energy degrader comprising: (1) a cylindrical member having a length;and (2) a distribution of wall thickness in a circumferential directionaround an axis of rotation, where thickness of the wall determinesenergy degradation of the irradiation beam.

Gantry

T. Yamashita, et. al. “Rotating Irradiation Apparatus”, U.S. Pat. No.7,381,979 (Jun. 3, 2008) describe a rotating gantry having a front ringand a rear ring, each ring having radial support devices, where theradial support devices have linear guides. The system has thrust supportdevices for limiting movement of the rotatable body in the direction ofthe rotational axis of the rotatable body.

T. Yamashita, et. al. “Rotating Gantry of Particle Beam Therapy System”U.S. Pat. No. 7,372,053 (May 13, 2008) describe a rotating gantrysupported by an air braking system allowing quick movement, braking, andstopping of the gantry during irradiation treatment.

M. Yanagisawa, et. al. “Medical Charged Particle Irradiation Apparatus”,U.S. Pat. No. 6,992,312 (Jan. 31, 2006); M. Yanagisawa, et. al. “MedicalCharged Particle Irradiation Apparatus”, U.S. Pat. No. 6,979,832 (Dec.27, 2005); and M. Yanagisawa, et. al. “Medical Charged ParticleIrradiation Apparatus”, U.S. Pat. No. 6,953,943 (Oct. 11, 2005) alldescribe an apparatus capable of irradiation from upward and horizontaldirections. The gantry is rotatable about an axis of rotation where theirradiation field forming device is eccentrically arranged, such that anaxis of irradiation passes through a different position than the axis ofrotation.

H. Kaercher, et. al. “Isokinetic Gantry Arrangement for the IsocentricGuidance of a Particle Beam And a Method for Constructing Same”, U.S.Pat. No. 6,897,451 (May 24, 2005) describe an isokinetic gantryarrangement for isocentric guidance of a particle beam that can berotated around a horizontal longitudinal axis.

G. Kraft, et. al. “Ion Beam System for Irradiating Tumor Tissues”, U.S.Pat. No. 6,730,921 (May 4, 2004) describe an ion beam system forirradiating tumor tissues at various irradiation angles in relation to ahorizontally arranged patient couch, where the patient couch isrotatable about a center axis and has a lifting mechanism. The systemhas a central ion beam deflection of up to ±15 degrees with respect to ahorizontal direction.

M. Pavlovic, et. al. “Gantry System and Method for Operating Same”, U.S.Pat. No. 6,635,882 (Oct. 21, 2003) describe a gantry system foradjusting and aligning an ion beam onto a target from a freelydeterminable effective treatment angle. The ion beam is aligned on atarget at adjustable angles of from 0 to 360 degrees around the gantryrotation axis and at an angle of 45 to 90 degrees off of the gantryrotation axis yielding a cone of irradiation when rotated a fullrevolution about the gantry rotation axis.

Respiration

K. Matsuda “Radioactive Beam Irradiation Method and Apparatus TakingMovement of the Irradiation Area Into Consideration”, U.S. Pat. No.5,538,494 (Jul. 23, 1996) describes a method and apparatus that enablesirradiation even in the case of a diseased part changing position due tophysical activity, such as breathing and heart beat. Initially, aposition change of a diseased body part and physical activity of thepatient are measured concurrently and a relationship therebetween isdefined as a function. Radiation therapy is performed in accordance tothe function.

Patient Positioning

Y. Nagamine, et. al. “Patient Positioning Device and Patient PositioningMethod”, U.S. Pat. No. 7,212,609 (May 1, 2007) and Y. Nagamine, et. al.“Patient Positioning Device and Patient Positioning Method”, U.S. Pat.No. 7,212,608 (May 1, 2007) describe a patient positioning system thatcompares a comparison area of a reference X-ray image and a currentX-ray image of a current patient location using pattern matching.

D. Miller, et. al. “Modular Patient Support System”, U.S. Pat. No.7,173,265 (Feb. 6, 2007) describe a radiation treatment system having apatient support system that includes a modularly expandable patient podand at least one immobilization device, such as a moldable foam cradle.

K. Kato, et. al. “Multi-Leaf Collimator and Medical System IncludingAccelerator”, U.S. Pat. No. 6,931,100 (Aug. 16, 2005); K. Kato, et. al.“Multi-Leaf Collimator and Medical System Including Accelerator”, U.S.Pat. No. 6,823,045 (Nov. 23, 2004); K. Kato, et. al. “Multi-LeafCollimator and Medical System Including Accelerator”, U.S. Pat. No.6,819,743 (Nov. 16, 2004); and K. Kato, et. al. “Multi-Leaf Collimatorand Medical System Including Accelerator”, U.S. Pat. No. 6,792,078 (Sep.14, 2004) all describe a system of leaf plates used to shortenpositioning time of a patient for irradiation therapy. Motor drivingforce is transmitted to a plurality of leaf plates at the same timethrough a pinion gear. The system also uses upper and lower aircylinders and upper and lower guides to position a patient.

Problem

There exists in the art of particle beam therapy of cancerous tumors aneed for an integrated charged particle cancer therapy system, which ispreferably compact, cost effective, accurate, and precise.

SUMMARY OF THE INVENTION

The invention comprises a charged particle beam path integrated into acharged particle cancer therapy method and apparatus.

DESCRIPTION OF THE FIGURES

FIG. 1 illustrates component connections of a particle beam therapysystem;

FIG. 2 illustrates a charged particle therapy system;

FIG. 3 illustrates an ion beam generation system;

FIG. 4 illustrates straight and turning sections of a synchrotron;

FIG. 5 illustrates bending magnets of a synchrotron;

FIG. 6 provides a perspective view of a bending magnet;

FIG. 7 illustrates a cross-sectional view of a bending magnet;

FIG. 8 illustrates a cross-sectional view of a bending magnet;

FIG. 9 illustrates a magnetic turning section of a synchrotron;

FIGS. 10A and B illustrate an RF accelerator and an RF acceleratorsubsystem, respectively;

FIG. 11 illustrates a magnetic field control system;

FIG. 12 illustrates a charged particle extraction and intensity controlsystem;

FIG. 13 illustrates a proton beam position verification system;

FIG. 14 illustrates a patient positioning system from: (A) a front viewand (B) a top view;

FIG. 15 provides X-ray and proton beam dose distributions;

FIGS. 16 A-E illustrate controlled depth of focus irradiation;

FIGS. 17 A-E illustrate multi-field irradiation;

FIG. 18 illustrates dose efficiency enhancement via use of multi-fieldirradiation;

FIG. 19 provides two methods of multi-field irradiation implementation;

FIG. 20 illustrates multi-dimensional scanning of a charged particlebeam spot scanning system operating on: (A) a 2-D slice or (B) a 3-Dvolume of a tumor;

FIG. 21 illustrates an electron gun source used in generating X-rayscoupled with a particle beam therapy system;

FIG. 22 illustrates an X-ray source proximate a particle beam path;

FIG. 23 illustrates an expanded X-ray beam path;

FIG. 24 provides an X-ray tomography system;

FIG. 25 illustrates a semi-vertical patient positioning system; and

FIG. 26 provides a method of coordinating X-ray collection with patientbreathing.

DETAILED DESCRIPTION OF THE INVENTION

The invention comprises a charged particle beam path integrated into acharged particle beam radiation method and apparatus for irradiation oftumors of a patient.

In one embodiment, the system comprises a charged particle beam path,through which charged particles flow. The charged particle beam pathcouples an injector, synchrotron accelerator, beam transport system,targeting system, and/or patient interface method and apparatus.

In another embodiment, the method and apparatus comprises a chargedparticle beam path coupling an injector, synchrotron accelerator, beamtransport system, targeting system, and/or patient interface method andapparatus used to irradiate a tumor of a patient. Preferably, theinjector comprises: a negative ion beam source, a two phase ion sourcevacuum system, an ion beam focusing lens, and/or a tandem accelerator.Preferably, the synchrotron comprises turning magnets, edge focusingmagnets, magnetic field concentration magnets, winding and correctioncoils, flat magnetic field incident surfaces, and/or extractionelements. Preferably, the beam transport system, targeting system, andpatient interface combine to allow multi-axis/multi-field irradiation,where multi-axis control comprises control of horizontal and verticalbeam position, beam energy, and beam intensity and multi-field controlcomprises control of patient rotation and distribution of deliveredenergy in and about the tumor in a time controlled, targeted, accurate,precise, dosage controlled, and efficient manner. In one example, thecharged particle beam path begins at the injector and ends in the tumoror above the rotatable platform holding the patients. In anotherexample, the charged particle beam path passes over the rotatableplatform holding the patient. In still another example, the chargedparticle beam path circumferentially surrounds the negative ion beam inthe injector, the circulating charged particles in the synchrotron,spans the charged particle beam path in the extraction step, or isproximate the charged particle beam path in the transport system fromthe synchrotron to the tumor. In still yet another example, the chargedparticle beam comprises the walls of the gap through which the protonstravel. In yet still another example, the charged particle beam pathpasses proximate to the X-ray generation source. Permutations andcombinations of the charged particle beam path include beam pathsurrounding any of the apparatus components described herein.

Used in combination with the method and apparatus, novel design featuresof a charged particle beam cancer therapy system are optionally used.Particularly, a negative ion beam source with novel features in thenegative ion source, ion source vacuum system, ion beam focusing lens,and tandem accelerator is described. Additionally, synchrotron turningmagnets, edge focusing magnets, magnetic field concentration magnets,winding and correction coils, flat magnetic field incident surfaces, andextraction elements are described that minimize the overall size of thesynchrotron, provide a tightly controlled proton beam, directly reducethe size of required magnetic fields, directly reduce required operatingpower, and allow continual acceleration of protons in a synchrotron evenduring a process of extracting protons from the synchrotron. The ionbeam source system and synchrotron are preferably computer integratedwith a patient imaging system and a patient interface includingrespiration monitoring sensors and patient positioning elements.Further, intensity control of a charged particle beam acceleration,extraction, and/or targeting method and apparatus used in conjunctionwith charged particle beam radiation therapy of cancerous tumors isdescribed. More particularly, intensity, energy, and timing control of acharged particle stream of a synchrotron is described. The synchrotroncontrol elements allow tight control of the charged particle beam, whichcompliments the tight control of patient positioning to yield efficienttreatment of a solid tumor with reduced tissue damage to surroundinghealthy tissue. In addition, the system reduces the overall size of thesynchrotron, provides a tightly controlled proton beam, directly reducesthe size of required magnetic fields, directly reduces requiredoperating power, and allows continual acceleration of protons in asynchrotron even during a process of extracting protons from thesynchrotron. All of these systems are preferably used in conjunctionwith an X-ray system capable of collecting X-rays of a patient in (1) apositioning system for proton treatment and (2) at a specified moment ofthe patient's respiration cycle. Combined, the systems provide forefficient, accurate, and precise noninvasive tumor treatment withminimal damage to surrounding healthy tissue.

Charged Particle Beam Therapy

Throughout this document, a charged particle beam therapy system, suchas a proton beam, hydrogen ion beam, or carbon ion beam, is described.Herein, the charged particle beam therapy system is described using aproton beam. However, the aspects taught and described in terms of aproton beam are not intended to be limiting to that of a proton beam andare illustrative of a charged particle beam system. Any charged particlebeam system is equally applicable to the techniques described herein.

Referring now to FIG. 1, a charged particle beam system 100 isillustrated. The charged particle beam preferably comprises a number ofsubsystems including any of: a main controller 110; an injection system120; a synchrotron 130 that typically includes: (1) an acceleratorsystem 132 and (2) an extraction system 134; ascanning/targeting/delivery system 140; a patient interface module 150;a display system 160; and/or an imaging system 170.

An exemplary method of use of the charged particle beam system 100 isprovided. The main controller 110 controls one or more of the subsystemsto accurately and precisely deliver protons to a tumor of a patient. Forexample, the main controller 110 obtains an image, such as a portion ofa body and/or of a tumor, from the imaging system 170. The maincontroller 110 also obtains position and/or timing information from thepatient interface module 150. The main controller 110 then optionallycontrols the injection system 120 to inject a proton into a synchrotron130. The synchrotron typically contains at least an accelerator system132 and an extraction system 134. The main controller preferablycontrols the proton beam within the accelerator system, such as bycontrolling speed, trajectory, and timing of the proton beam. The maincontroller then controls extraction of a proton beam from theaccelerator through the extraction system 134. For example, thecontroller controls timing, energy, and/or intensity of the extractedbeam. The controller 110 also preferably controls targeting of theproton beam through the scanning/targeting/delivery system 140 to thepatient interface module 150. One or more components of the patientinterface module 150 are preferably controlled by the main controller110. Further, display elements of the display system 160 are preferablycontrolled via the main controller 110. Displays, such as displayscreens, are typically provided to one or more operators and/or to oneor more patients. In one embodiment, the main controller 110 times thedelivery of the proton beam from all systems, such that protons aredelivered in an optimal therapeutic manner to the patient.

Herein, the main controller 110 refers to a single system controllingthe charged particle beam system 100, to a single controller controllinga plurality of subsystems controlling the charged particle beam system100, or to a plurality of individual controllers controlling one or moresub-systems of the charged particle beam system 100.

Synchrotron

Herein, the term synchrotron is used to refer to a system maintainingthe charged particle beam in a circulating path; however, cyclotrons arealternatively used, albeit with their inherent limitations of energy,intensity, and extraction control. Further, the charged particle beam isreferred to herein as circulating along a circulating path about acentral point of the synchrotron. The circulating path is alternativelyreferred to as an orbiting path; however, the orbiting path does notrefer a perfect circle or ellipse, rather it refers to cycling of theprotons around a central point or region.

Referring now to FIG. 2, an illustrative exemplary embodiment of oneversion of the charged particle beam system 100 is provided. The number,position, and described type of components is illustrative andnon-limiting in nature. In the illustrated embodiment, an injectorsystem 210 or ion source or charged particle beam source generatesprotons. The protons are delivered into a vacuum tube that runs into,through, and out of the synchrotron. The generated protons are deliveredalong an initial path 262. Focusing magnets 230, such as quadrupolemagnets or injection quadrupole magnets, are used to focus the protonbeam path. A quadrupole magnet is a focusing magnet. An injector bendingmagnet 232 bends the proton beam toward the plane of the synchrotron130. The focused protons having an initial energy are introduced into aninjector magnet 240, which is preferably an injection Lamberson magnet.Typically, the initial beam path 262 is along an axis off of, such asabove, a circulating plane of the synchrotron 130. The injector bendingmagnet 232 and injector magnet 240 combine to move the protons into thesynchrotron 130. Main bending magnets 250 or dipole magnets orcirculating magnets are used to turn the protons along a circulatingbeam path 264. A dipole magnet is a bending magnet. The main bendingmagnets 250 bend the initial beam path 262 into a circulating beam path264. In this example, the main bending magnets 250 or circulatingmagnets are represented as four sets of four magnets to maintain thecirculating beam path 264 into a stable circulating beam path. However,any number of magnets or sets of magnets are optionally used to move theprotons around a single orbit in the circulation process. The protonspass through an accelerator 270. The accelerator accelerates the protonsin the circulating beam path 264. As the protons are accelerated, thefields applied by the magnets are increased. Particularly, the speed ofthe protons achieved by the accelerator 270 are synchronized withmagnetic fields of the main bending magnets 250 or circulating magnetsto maintain stable circulation of the protons about a central point orregion 280 of the synchrotron. At separate points in time theaccelerator 270/main bending magnet 250 combination is used toaccelerate and/or decelerate the circulating protons while maintainingthe protons in the circulating path or orbit. An extraction element ofthe inflector/deflector system 290 is used in combination with aLamberson extraction magnet 292 to remove protons from their circulatingbeam path 264 within the synchrotron 130. One example of a deflectorcomponent is a Lamberson magnet. Typically the deflector moves theprotons from the circulating plane to an axis off of the circulatingplane, such as above the circulating plane. Extracted protons arepreferably directed and/or focused using an extraction bending magnet237 and extraction focusing magnets 235, such as quadrupole magnetsalong a transport path 268 into the scanning/targeting/delivery system140. Two components of a scanning system 140 or targeting systemtypically include a first axis control 142, such as a vertical control,and a second axis control 144, such as a horizontal control. In oneembodiment, the first axis control 142 allows for about 100 mm ofvertical scanning of the proton beam 268 and the second axis control 144allows for about 700 mm of horizontal scanning of the proton beam 268. Anozzle system 146 is used for imaging the proton beam and/or as a vacuumbarrier between the low pressure beam path of the synchrotron and theatmosphere. Protons are delivered with control to the patient interfacemodule 150 and to a tumor of a patient. All of the above listed elementsare optional and may be used in various permutations and combinations.

Ion Beam Generation System

An ion beam generation system generates a negative ion beam, such as ahydrogen anion or H⁻ beam; preferably focuses the negative ion beam;converts the negative ion beam to a positive ion beam, such as a protonor H⁺ beam; and injects the positive ion beam into the synchrotron 130.Portions of the ion beam path are preferably under partial vacuum. Eachof these systems are further described, infra.

Referring now to FIG. 3, an exemplary ion beam generation system 300 isillustrated. As illustrated, the ion beam generation system 300 has fourmajor elements: a negative ion source 310, a first partial vacuum system330, an optional ion beam focusing system 350, and a tandem accelerator390.

Still referring to FIG. 3, the negative ion source 310 preferablyincludes an inlet port 312 for injection of hydrogen gas into a hightemperature plasma chamber 314. In one embodiment, the plasma chamberincludes a magnetic material 316, which provides a magnetic fieldbarrier 317 between the high temperature plasma chamber 314 and a lowtemperature plasma region on the opposite side of the magnetic fieldbarrier. An extraction pulse is applied to a negative ion extractionelectrode 318 to pull the negative ion beam into a negative ion beampath 319, which proceeds through the first partial vacuum system 330,through the ion beam focusing system 350, and into the tandemaccelerator 390.

Still referring to FIG. 3, the first partial vacuum system 330 is anenclosed system running from the hydrogen gas inlet port 312 to thetandem accelerator 390 input foil 395. The input foil 395 is sealeddirectly or indirectly to the edges of the vacuum tube 320 providing fora higher pressure, such as about 10⁻⁵ torr, to be maintained on thefirst partial vacuum system 330 side of the foil 395 and a lowerpressure, such as about 10⁻⁷ torr, to be maintained on the synchrotronside of the foil 390. By only pumping first partial vacuum system 330and by only semi-continuously operating the ion beam source vacuum basedon sensor readings, the lifetime of the semi-continuously operating pumpis extended. The sensor readings are further described, infra.

Still referring to FIG. 3, the first partial vacuum system 330preferably includes: a first pump 332, such as a continuously operatingpump and/or a turbo molecular pump; a large holding volume 334; and asemi-continuously operating pump 336. Preferably, a pump controller 340receives a signal from a pressure sensor 342 monitoring pressure in thelarge holding volume 334. Upon a signal representative of a sufficientpressure in the large holding volume 334, the pump controller 340instructs an actuator 345 to open a valve 346 between the large holdingvolume and the semi-continuously operating pump 336 and instructs thesemi-continuously operating pump to turn on and pump to atmosphereresidual gases out of the vacuum line 320 about the charged particlestream. In this fashion, the lifetime of the semi-continuously operatingpump is extended by only operating semi-continuously and as needed. Inone example, the semi-continuously operating pump 336 operates for a fewminutes every few hours, such as 5 minutes every 4 hours, therebyextending a pump with a lifetime of about 2,000 hours to about 96,000hours.

Further, by isolating the inlet gas from the synchrotron vacuum system,the synchrotron vacuum pumps, such as turbo molecular pumps can operateover a longer lifetime as the synchrotron vacuum pumps have fewer gasmolecules to deal with. For example, the inlet gas is primarily hydrogengas but may contain impurities, such as nitrogen and carbon dioxide. Byisolating the inlet gases in the negative ion source system 310, firstpartial vacuum system 330, ion beam focusing system 350 and negative ionbeam side of the tandem accelerator 390, the synchrotron vacuum pumpscan operate at lower pressures with longer lifetimes, which increasesthe efficiency of the synchrotron 130.

Still referring to FIG. 3, the ion beam focusing system 350 includes twoor more electrodes where one electrode of each electrode pair partiallyobstructs the ion beam path with conductive paths 372, such as aconductive mesh. In the illustrated example, three ion beam focusingsystem sections are illustrated, a two electrode ion focusing section360, a first three electrode ion focusing section 370, and a secondthree electrode ion focusing section 380. In a given electrode pair,electric field lines, running between the conductive mesh of a firstelectrode and a second electrode, provide inward forces focusing thenegative ion beam. Multiple such electrode pairs provide multiplenegative ion beam focusing regions. Preferably the two electrode ionfocusing section 360, first three electrode ion focusing section 370,and second three electrode ion focusing section 380 are placed after thenegative ion source and before the tandem accelerator and/or cover aspace of about 0.5, 1, or 2 meters along the ion beam path. Ion beamfocusing systems are further described, infra.

Still referring to FIG. 3, the tandem accelerator 390 preferablyincludes a foil 395, such as a carbon foil. The negative ions in thenegative ion beam path 319 are converted to positive ions, such asprotons, and the initial ion beam path 262 results. The foil 395 ispreferably sealed directly or indirectly to the edges of the vacuum tube320 providing for a higher pressure, such as about 10⁻⁵ torr, to bemaintained on the side of the foil 395 having the negative ion beam path319 and a lower pressure, such as about 10⁻⁷ torr, to be maintained onthe side of the foil 390 having the proton ion beam path 262. Having thefoil 395 physically separating the vacuum chamber 320 into two pressureregions allows for a system having fewer and/or smaller pumps tomaintain the lower pressure system in the synchrotron 130 as the inlethydrogen and its residuals are extracted in a separate contained andisolated space by the first partial vacuum system 330.

Referring again to FIG. 1, another exemplary method of use of thecharged particle beam system 100 is provided. The main controller 110,or one or more sub-controllers, controls one or more of the subsystemsto accurately and precisely deliver protons to a tumor of a patient. Forexample, the main controller sends a message to the patient indicatingwhen or how to breath. The main controller 110 obtains a sensor readingfrom the patient interface module, such as a temperature breath sensoror a force reading indicative of where in a breath cycle the subject is.The main controller collects an image, such as a portion of a bodyand/or of a tumor, from the imaging system 170. The main controller 110also obtains position and/or timing information from the patientinterface module 150. The main controller 110 then optionally controlsthe injection system 120 to inject hydrogen gas into a negative ion beamsource 310 and controls timing of extraction of the negative ion fromthe negative ion beam source 310. Optionally, the main controllercontrols ion beam focusing the ion beam focusing lens system 350;acceleration of the proton beam with the tandem accelerator 390; and/orinjection of the proton into the synchrotron 130. The synchrotrontypically contains at least an accelerator system 132 and an extractionsystem 134. The synchrotron preferably contains one or more of: turningmagnets, edge focusing magnets, magnetic field concentration magnets,winding and correction coils, and flat magnetic field incident surfaces,some of which contain elements under control by the main controller 110.The main controller preferably controls the proton beam within theaccelerator system, such as by controlling speed, trajectory, and/ortiming of the proton beam. The main controller then controls extractionof a proton beam from the accelerator through the extraction system 134.For example, the controller controls timing, energy, and/or intensity ofthe extracted beam. The controller 110 also preferably controlstargeting of the proton beam through the targeting/delivery system 140to the patient interface module 150. One or more components of thepatient interface module 150 are preferably controlled by the maincontroller 110, such as vertical position of the patient, rotationalposition of the patient, and patient chairpositioning/stabilization/control elements. Further, display elements ofthe display system 160 are preferably controlled via the main controller110. Displays, such as display screens, are typically provided to one ormore operators and/or to one or more patients. In one embodiment, themain controller 110 times the delivery of the proton beam from allsystems, such that protons are delivered in an optimal therapeuticmanner to the patient.

Circulating System

A synchrotron 130 preferably comprises a combination of straightsections 410 and ion beam turning sections 420. Hence, the circulatingpath of the protons is not circular in a synchrotron, but is rather apolygon with rounded corners.

In one illustrative embodiment, the synchrotron 130, which as alsoreferred to as an accelerator system, has four straight elements andfour turning sections. Examples of straight sections 410 include the:inflector 240, accelerator 270, extraction system 290, and deflector292. Along with the four straight sections are four ion beam turningsections 420, which are also referred to as magnet sections or turningsections. Turning sections are further described, infra.

Referring now to FIG. 4, an exemplary synchrotron is illustrated. Inthis example, protons delivered along the initial proton beam path 262are inflected into the circulating beam path with the inflector 240 andafter acceleration are extracted via a deflector 292 to a beam transportpath 268. In this example, the synchrotron 130 comprises four straightsections 410 and four bending or turning sections 420 where each of thefour turning sections use one or more magnets to turn the proton beamabout ninety degrees. As is further described, infra, the ability toclosely space the turning sections and efficiently turn the proton beamresults in shorter straight sections. Shorter straight sections allowsfor a synchrotron design without the use of focusing quadrupoles in thecirculating beam path of the synchrotron. The removal of the focusingquadrupoles from the circulating proton beam path results in a morecompact design. In this example, the illustrated synchrotron has about afive meter diameter versus eight meter and larger cross-sectionaldiameters for systems using a quadrupole focusing magnet in thecirculating proton beam path.

Referring now to FIG. 5, additional description of the first bending orturning section 420 is provided. Each of the turning sections preferablycomprises multiple magnets, such as about 2, 4, 6, 8, 10, or 12 magnets.In this example, four turning magnets 510, 520, 530, 540 in the firstturning section 420 are used to illustrate key principles, which are thesame regardless of the number of magnets in a turning section 420. Aturning magnet 510 is a particular type of main bending or circulatingmagnet 250.

In physics, the Lorentz force is the force on a point charge due toelectromagnetic fields. The Lorentz force is given by equation 1 interms of magnetic fields with the election field terms not included.F=q(v×B)  eq. 1

In equation 1, F is the force in newtons; B is the magnetic field inTeslas; and v is the instantaneous velocity of the particles in metersper second.

Referring now to FIG. 6, an example of a single magnet bending orturning section 510 is expanded. The turning section includes a gap 610through which protons circulate. The gap 610 is preferably a flat gap,allowing for a magnetic field across the gap 610 that is more uniform,even, and intense. A magnetic field enters the gap 610 through amagnetic field incident surface and exits the gap 610 through a magneticfield exiting surface. The gap 610 runs in a vacuum tube between twomagnet halves. The gap 610 is controlled by at least two parameters: (1)the gap 610 is kept as large as possible to minimize loss of protons and(2) the gap 610 is kept as small as possible to minimize magnet sizesand the associated size and power requirements of the magnet powersupplies. The flat nature of the gap 610 allows for a compressed andmore uniform magnetic field across the gap 610. One example of a gapdimension is to accommodate a vertical proton beam size of about 2 cmwith a horizontal beam size of about 5 to 6 cm.

As described, supra, a larger gap size requires a larger power supply.For instance, if the gap 610 size doubles in vertical size, then thepower supply requirements increase by about a factor of 4. The flatnessof the gap 610 is also important. For example, the flat nature of thegap 610 allows for an increase in energy of the extracted protons fromabout 250 to about 330 MeV. More particularly, if the gap 610 has anextremely flat surface, then the limits of a magnetic field of an ironmagnet are reachable. An exemplary precision of the flat surface of thegap 610 is a polish of less than about 5 microns and preferably with apolish of about 1 to 3 microns. Unevenness in the surface results inimperfections in the applied magnetic field. The polished flat surfacespreads unevenness of the applied magnetic field.

Still referring to FIG. 6, the charged particle beam moves through thegap 610 with an instantaneous velocity, v. A first magnetic coil 620 anda second magnetic coil 630 run above and below the gap 610,respectively. Current running through the coils 620, 630 results in amagnetic field, B, running through the single magnet turning section510. In this example, the magnetic field, B, runs upward, which resultsin a force, F, pushing the charged particle beam inward toward a centralpoint of the synchrotron, which turns the charged particle beam in anarc.

Still referring to FIG. 6, a portion of an optional second magnetbending or turning section 520 is illustrated. The coils 620, 630typically have return elements 640, 650 or turns at the end of onemagnet, such as at the end of the first magnet turning section 510. Theturns 640, 650 take space. The space reduces the percentage of the pathabout one orbit of the synchrotron that is covered by the turningmagnets. This leads to portions of the circulating path where theprotons are not turned and/or focused and allows for portions of thecirculating path where the proton path defocuses. Thus, the spaceresults in a larger synchrotron. Therefore, the space between magnetturning sections 660 is preferably minimized. The second turning magnetis used to illustrate that the coils 620, 630 optionally run along aplurality of magnets, such as 2, 3, 4, 5, 6, or more magnets. Coils 620,630 running across multiple turning section magnets allows for twoturning section magnets to be spatially positioned closer to each otherdue to the removal of the steric constraint of the turns, which reducesand/or minimizes the space 660 between two turning section magnets.

Referring now to FIGS. 7 and 8, two illustrative 90 degree rotatedcross-sections of single magnet bending or turning sections 510 arepresented. Referring now to FIG. 8, the magnet assembly has a firstmagnet 810 and a second magnet 820. A magnetic field induced by coils,described infra, runs between the first magnet 810 to the second magnet820 across the gap 610. Return magnetic fields run through a first yoke812 and second yoke 822. The combined cross-section area of the returnyokes roughly approximates the cross-sectional area of the first magnet810 or second magnet 820. The charged particles run through the vacuumtube in the gap 610. As illustrated, protons run into FIG. 8 through thegap 610 and the magnetic field, illustrated as vector B, applies a forceF to the protons pushing the protons towards the center of thesynchrotron, which is off page to the right in FIG. 8. The magneticfield is created using windings. A first coil makes up a first windingcoil 850 and a second coil of wire makes up a second winding coil 860.Isolating or concentrating gaps 830, 840, such as air gaps, isolate theiron based yokes from the gap 610. The gap 610 is approximately flat toyield a uniform magnetic field across the gap 610, as described supra.

Still again to FIG. 7, the ends of a single bending or turning magnetare preferably beveled. Nearly perpendicular or right angle edges of aturning magnet 510 are represented by dashed lines 774, 784. The dashedlines 774, 784 intersect at a point 790 beyond the center of thesynchrotron 280. Preferably, the edge of the turning magnet is beveledat angles alpha, α, and beta, β, which are angles formed by a first line772, 782 going from an edge of the turning magnet 510 and the center 280and a second line 774, 784 going from the same edge of the turningmagnet and the intersecting point 790. The angle alpha is used todescribe the effect and the description of angle alpha applies to anglebeta, but angle alpha is optionally different from angle beta. The anglealpha provides an edge focusing effect. Beveling the edge of the turningmagnet 510 at angle alpha focuses the proton beam.

Multiple turning magnets provide multiple magnet edges that each haveedge focusing effects in the synchrotron 130. If only one turning magnetis used, then the beam is only focused once for angle alpha or twice forangle alpha and angle beta. However, by using smaller turning magnets,more turning magnets fit into the turning sections 420 of thesynchrotron 130. For example, if four magnets are used in a turningsection 420 of the synchrotron, then for a single turning section thereare eight possible edge focusing effect surfaces, two edges per magnet.The eight focusing surfaces yield a smaller cross-sectional beam size.This allows the use of a smaller gap 610.

The use of multiple edge focusing effects in the turning magnets resultsin not only a smaller gap 610, but also the use of smaller magnets andsmaller power supplies. For a synchrotron 130 having four turningsections 420 where each turning sections has four turning magnets andeach turning magnet has two focusing edges, a total of thirty-twofocusing edges exist for each orbit of the protons in the circulatingpath of the synchrotron 130. Similarly, if 2, 6, or 8 magnets are usedin a given turning section, or if 2, 3, 5, or 6 turning sections areused, then the number of edge focusing surfaces expands or contractsaccording to equation 2.

$\begin{matrix}{{TFE} = {{NTS}*\frac{M}{NTS}*\frac{FE}{M}}} & {{eq}.\mspace{14mu} 2}\end{matrix}$where TFE is the number of total focusing edges, NTS is the number ofturning sections, M is the number of magnets, and FE is the number offocusing edges. Naturally, not all magnets are necessarily beveled andsome magnets are optionally beveled on only one edge.

The inventors have determined that multiple smaller magnets havebenefits over fewer larger magnets. For example, the use of 16 smallmagnets yields 32 focusing edges whereas the use of 4 larger magnetsyields only 8 focusing edges. The use of a synchrotron having morefocusing edges results in a circulating path of the synchrotron builtwithout the use of focusing quadrupoles magnets. All prior artsynchrotrons use quadrupoles in the circulating path of the synchrotron.Further, the use of quadrupoles in the circulating path necessitatesadditional straight sections in the circulating path of the synchrotron.Thus, the use of quadrupoles in the circulating path of a synchrotronresults in synchrotrons having larger diameters, circulating beampathlengths, and/or larger circumferences.

In various embodiments of the system described herein, the synchrotronhas any combination of:

-   -   at least 4 and preferably 6, 8, 10, or more edge focusing edges        per 90 degrees of turn of the charged particle beam in a        synchrotron having four turning sections;    -   at least about 16 and preferably about 24, 32, or more edge        focusing edges per orbit of the charged particle beam in the        synchrotron;    -   only 4 turning sections where each of the turning sections        includes at least 4 and preferably 8 edge focusing edges;    -   an equal number of straight sections and turning sections;    -   exactly 4 turning sections;    -   at least 4 edge focusing edges per turning section;    -   no quadrupoles in the circulating path of the synchrotron;    -   a rounded corner rectangular polygon configuration;    -   a circumference of less than 60 meters;    -   a circumference of less than 60 meters and 32 edge focusing        surfaces; and/or    -   any of about 8, 16, 24, or 32 non-quadrupole magnets per        circulating path of the synchrotron, where the non-quadrupole        magnets include edge focusing edges.

Referring again to FIG. 8, the incident magnetic field surface 870 ofthe first magnet 810 is further described. FIG. 8 is not to scale and isillustrative in nature. Local imperfections or unevenness in quality ofthe finish of the incident surface 870 results in inhomogeneities orimperfections in the magnetic field applied to the gap 610. Preferably,the incident surface 870 is flat, such as to within about a zero tothree micron finish polish, or less preferably to about a ten micronfinish polish.

Referring still to FIG. 8, additional magnet elements are described. Thefirst magnet 810 preferably contains an initial cross sectional distance890 of the iron based core. The contours of the magnetic field areshaped by the magnets 810, 820 and the yokes 812, 822. The iron basedcore tapers to a second cross sectional distance 892. The magnetic fieldin the magnet preferentially stays in the iron based core as opposed tothe gaps 830, 840. As the cross-sectional distance decreases from theinitial cross sectional distance 890 to the final cross-sectionaldistance 892, the magnetic field concentrates. The change in shape ofthe magnet from the longer distance 890 to the smaller distance 892 actsas an amplifier. The concentration of the magnetic field is illustratedby representing an initial density of magnetic field vectors 894 in theinitial cross section 890 to a concentrated density of magnetic fieldvectors 896 in the final cross section 892. The concentration of themagnetic field due to the geometry of the turning magnets results infewer winding coils 850, 860 being required and also a smaller powersupply to the coils being required.

In one example, the initial cross-section distance 890 is about fifteencentimeters and the final cross-section distance 892 is about tencentimeters. Using the provided numbers, the concentration of themagnetic field is about 15/10 or 1.5 times at the incident surface 870of the gap 610, though the relationship is not linear. The taper 842 hasa slope, such as about 20, 40, or 60 degrees. The concentration of themagnetic field, such as by 1.5 times, leads to a corresponding decreasein power consumption requirements to the magnets.

Referring still to FIG. 8, the first magnet 810 preferably contains aninitial cross sectional distance 890 of the iron based core. Thecontours of the magnetic field are shaped by the magnets 810, 820 andthe yokes 812, 822. In this example, the core tapers to a second crosssectional distance 892 with a smaller angle theta, θ. As described,supra, the magnetic field in the magnet preferentially stays in the ironbased core as opposed to the gaps 830, 840. As the cross-sectionaldistance decreases from the initial cross sectional distance 890 to thefinal cross-sectional distance 892, the magnetic field concentrates. Thesmaller angle, theta, results in a greater amplification of the magneticfield in going from the longer distance 890 to the smaller distance 892.The concentration of the magnetic field is illustrated by representingan initial density of magnetic field vectors 894 in the initial crosssection 890 to a concentrated density of magnetic field vectors 896 inthe final cross section 892. The concentration of the magnetic field dueto the geometry of the turning magnets results in fewer winding coils850, 860 being required and also a smaller power supply to the windingcoils 850, 860 being required.

Still referring to FIG. 8, optional correction coils 852, 862 areillustrated that are used to correct the strength of one or more turningmagnets. The correction coils 852, 862 supplement the winding coils 850,860. The correction coils 852, 862 have correction coil power suppliesthat are separate from winding coil power supplies used with the windingcoils 850, 860. The correction coil power supplies typically operate ata fraction of the power required compared to the winding coil powersupplies, such as about 1, 2, 3, 5, 7, or 10 percent of the power andmore preferably about 1 or 2 percent of the power used with the windingcoils 850, 860. The smaller operating power applied to the correctioncoils 852, 862 allows for more accurate and/or precise control of thecorrection coils. Correction coils are used to adjust for imperfectionin the turning magnets 510, 520, 530, 540. Optionally, separatecorrection coils are used for each turning magnet allowing individualtuning of the magnetic field for each turning magnet, which easesquality requirements in the manufacture of each turning magnet.

Referring now to FIG. 9, an example of winding coils and correctioncoils about a plurality of turning magnets 510, 520, 530, 540 in an ionbeam turning section 420 is illustrated. One or more high precisionmagnetic field sensors are placed into the synchrotron and are used tomeasure the magnetic field at or near the proton beam path. For example,the magnetic sensors 950 are optionally placed between turning magnetsand/or within a turning magnet, such as at or near the gap 610 or at ornear the magnet core or yoke. The sensors are part of a feedback systemto the correction coils. Thus, the system preferably stabilizes themagnetic field in the synchrotron elements rather that stabilizing thecurrent applied to the magnets. Stabilization of the magnetic fieldallows the synchrotron to come to a new energy level quickly. Thisallows the system to be controlled to an operator or algorithm selectedenergy level with each pulse of the synchrotron and/or with each breathof the patient.

The winding and/or correction coils correct 1, 2, 3, or 4 turningmagnets, and preferably correct a magnetic field generated by twoturning magnets. A winding or correction coil covering multiple magnetsreduces space between magnets as fewer winding or correction coil endsare required, which occupy space.

Referring now to FIG. 10A and FIG. 10B, the accelerator system 270, suchas a radio-frequency (RF) accelerator system, is further described. Theaccelerator includes a series of coils 1010-1019, such as iron orferrite coils, each circumferentially enclosing the vacuum system 320through which the proton beam 264 passes in the synchrotron 130.Referring now to FIG. 10B, the first coil 1010 is further described. Aloop of standard wire 1030 completes at least one turn about the firstcoil 1010. The loop attaches to a microcircuit 1020. Referring again toFIG. 10A, an RF synthesizer 1040, which is preferably connected to themain controller 110, provides a low voltage RF signal that issynchronized to the period of circulation of protons in the proton beampath 264. The RF synthesizer 1040, microcircuit 1020, loop 1030, andcoil 1010 combine to provide an accelerating voltage to the protons inthe proton beam path 264. For example, the RF synthesizer 1040 sends asignal to the microcircuit 1020, which amplifies the low voltage RFsignal and yields an acceleration voltage, such as about 10 volts. Theactual acceleration voltage for a single microcircuit/loop/coilcombination is about 5, 10, 15, or 20 volts, but is preferably about 10volts. Preferably, the RF-amplifier microcircuit and accelerating coilare integrated.

Still referring to FIG. 10A, the integrated RF-amplifier microcircuitand accelerating coil presented in FIG. 10B is repeated, as illustratedas the set of coils 1011-1019 surrounding the vacuum tube 320. Forexample, the RF-synthesizer 1040, under main controller 130 direction,sends an RF-signal to the microcircuits 1020-1029 connected to coils1010-1019, respectively. Each of the microcircuit/loop/coil combinationsgenerates a proton accelerating voltage, such as about 10 volts each.Hence, a set of five coil combinations generates about 50 volts forproton acceleration. Preferably about 5 to 20 microcircuit/loop/coilcombinations are used and more preferably about 9 or 10microcircuit/loop/coil combinations are used in the accelerator system270.

As a further clarifying example, the RF synthesizer 1040 sends anRF-signal, with a period equal to a period of circulation of a protonabout the synchrotron 130, to a set of ten microcircuit/loop/coilcombinations, which results in about 100 volts for acceleration of theprotons in the proton beam path 264. The 100 volts is generated at arange of frequencies, such as at about 1 MHz for a low energy protonbeam to about 15 MHz for a high energy proton beam. The RF-signal isoptionally set at an integer multiple of a period of circulation of theproton about the synchrotron circulating path. Each of themicrocircuit/loop/coil combinations are optionally independentlycontrolled in terms of acceleration voltage and frequency.

Integration of the RF-amplifier microcircuit and accelerating coil, ineach microcircuit/loop/coil combination, results in three considerableadvantages. First, for synchrotrons, the prior art does not usemicrocircuits integrated with the accelerating coils but rather uses aset of long cables to provide power to a corresponding set of coils. Thelong cables have an impedance/resistance, which is problematic for highfrequency RF control. As a result, the prior art system is not operableat high frequencies, such as above about 10 MHz. The integratedRF-amplifier microcircuit/accelerating coil system is operable at aboveabout 10 MHz and even 15 MHz where the impedance and/or resistance ofthe long cables in the prior art systems results in poor control orfailure in proton acceleration. Second, the long cable system, operatingat lower frequencies, costs about $50,000 and the integratedmicrocircuit system costs about $1000, which is 50 times less expensive.Third, the microcircuit/loop/coil combinations in conjunction with theRF-amplifier system results in a compact low power consumption designallowing production and use of a proton cancer therapy system is a smallspace, as described supra, and in a cost effective manner.

Referring now to FIG. 11, an example is used to clarify the magneticfield control using a feedback loop 1100 to change delivery times and/orperiods of proton pulse delivery. In one case, a respiratory sensor 1110senses the breathing cycle of the subject. The respiratory sensor sendsthe information to an algorithm in a magnetic field controller 1120,typically via the patient interface module 150 and/or via the maincontroller 110 or a subcomponent thereof. The algorithm predicts and/ormeasures when the subject is at a particular point in the breathingcycle, such as at the bottom of a breath. Magnetic field sensors 1130are used as input to the magnetic field controller, which controls amagnet power supply 1140 for a given magnetic field 1150, such as withina first turning magnet 510 of a synchrotron 130. The control feedbackloop is thus used to dial the synchrotron to a selected energy level anddeliver protons with the desired energy at a selected point in time,such as at the bottom of the breath. More particularly, the maincontroller injects protons into the synchrotron and accelerates theprotons in a manner that combined with extraction delivers the protonsto the tumor at a selected point in the breathing cycle. Intensity ofthe proton beam is also selectable and controllable by the maincontroller at this stage. The feedback control to the correction coilsallows rapid selection of energy levels of the synchrotron that are tiedto the patient's breathing cycle. This system is in stark contrast to asystem where the current is stabilized and the synchrotron deliverpulses with a period, such as 10 or 20 cycles per second with a fixedperiod. Optionally, the feedback or the magnetic field design coupledwith the correction coils allows for the extraction cycle to match thevarying respiratory rate of the patient.

Traditional extraction systems do not allow this control as magnets havememories in terms of both magnitude and amplitude of a sine wave. Hence,in a traditional system, in order to change frequency, slow changes incurrent must be used. However, with the use of the feedback loop usingthe magnetic field sensors, the frequency and energy level of thesynchrotron are rapidly adjustable. Further aiding this process is theuse of a novel extraction system that allows for acceleration of theprotons during the extraction process, described infra.

Example III

Referring again to FIG. 9, an example of a winding coil 930 that coverstwo turning magnets 510, 520 is provided. Optionally, a first windingcoil 940 covers one magnets or a second winding coil 920 covers aplurality of magnets 510, 520. As described, supra, this system reducesspace between turning section allowing more magnetic field to be appliedper radian of turn. A first correction coil 910 is illustrated that isused to correct the magnetic field for the first turning magnet 510. Asecond correction coil 920 is illustrated that is used to correct themagnetic field for a winding coil 930 about two turning magnets.Individual correction coils for each turning magnet are preferred andindividual correction coils yield the most precise and/or accuratemagnetic field in each turning section. Particularly, the individualcorrection coil 910 is used to compensate for imperfections in theindividual magnet of a given turning section. Hence, with a series ofmagnetic field sensors, corresponding magnetic fields are individuallyadjustable in a series of feedback loops, via a magnetic fieldmonitoring system, as an independent coil is used for each turningsection. Alternatively, a multiple magnet correction coil is used tocorrect the magnetic field for a plurality of turning section magnets.

Flat Gap Surface

While the gap surface is described in terms of the first turning magnet510, the discussion applies to each of the turning magnets in thesynchrotron. Similarly, while the gap 610 surface is described in termsof the magnetic field incident surface 670, the discussion additionallyoptionally applies to the magnetic field exiting surface 680.

The magnetic field incident surface 870 of the first magnet 810 ispreferably about flat, such as to within about a zero to three micronfinish polish or less preferably to about a ten micron finish polish. Bybeing very flat, the polished surface spreads the unevenness of theapplied magnetic field across the gap 610. The very flat surface, suchas about 0, 1, 2, 4, 6, 8, 10, 15, or 20 micron finish, allows for asmaller gap size, a smaller applied magnetic field, smaller powersupplies, and tighter control of the proton beam cross-sectional area.The magnetic field exiting surface 880 is also preferably flat.

Proton Beam Extraction

Referring now to FIG. 12, an exemplary proton extraction process fromthe synchrotron 130 is illustrated. For clarity, FIG. 12 removeselements represented in FIG. 2, such as the turning magnets, whichallows for greater clarity of presentation of the proton beam path as afunction of time. Generally, protons are extracted from the synchrotron130 by slowing the protons. As described, supra, the protons wereinitially accelerated in a circulating path 264, which is maintainedwith a plurality of main bending magnets 250. The circulating path isreferred to herein as an original central beamline 264. The protonsrepeatedly cycle around a central point in the synchrotron 280. Theproton path traverses through a radio frequency (RF) cavity system 1210.To initiate extraction, an RF field is applied across a first blade 1212and a second blade 1214, in the RF cavity system 1210. The first blade1212 and second blade 1214 are referred to herein as a first pair ofblades.

In the proton extraction process, an RF voltage is applied across thefirst pair of blades, where the first blade 1212 of the first pair ofblades is on one side of the circulating proton beam path 264 and thesecond blade 1214 of the first pair of blades is on an opposite side ofthe circulating proton beam path 264. The applied RF field appliesenergy to the circulating charged-particle beam. The applied RF fieldalters the orbiting or circulating beam path slightly of the protonsfrom the original central beamline 264 to an altered circulating beampath 265. Upon a second pass of the protons through the RF cavitysystem, the RF field further moves the protons off of the originalproton beamline 264. For example, if the original beamline is consideredas a circular path, then the altered beamline is slightly elliptical.The applied RF field is timed to apply outward or inward movement to agiven band of protons circulating in the synchrotron accelerator. Eachorbit of the protons is slightly more off axis compared to the originalcirculating beam path 264. Successive passes of the protons through theRF cavity system are forced further and further from the originalcentral beamline 264 by altering the direction and/or intensity of theRF field with each successive pass of the proton beam through the RFfield.

The RF voltage is frequency modulated at a frequency about equal to theperiod of one proton cycling around the synchrotron for one revolutionor at a frequency than is an integral multiplier of the period of oneproton cycling about the synchrotron. The applied RF frequency modulatedvoltage excites a betatron oscillation. For example, the oscillation isa sine wave motion of the protons. The process of timing the RF field toa given proton beam within the RF cavity system is repeated thousands oftimes with each successive pass of the protons being moved approximatelyone micrometer further off of the original central beamline 264. Forclarity, the approximately 1000 changing beam paths with each successivepath of a given band of protons through the RF field are illustrated asthe altered beam path 265.

With a sufficient sine wave betatron amplitude, the altered circulatingbeam path 265 touches a material 1230, such as a foil an extractionfoil, an extraction material or a sheet of foil. The foil is preferablya lightweight material, such as beryllium, a lithium hydride, a carbonsheet, or a material of low nuclear charge. A material of low nuclearcharge is a material composed of atoms consisting essentially of atomshaving six or fewer protons. The foil is preferably about 10 to 150microns thick, is more preferably 30 to 100 microns thick, and is stillmore preferably 40-60 microns thick. In one example, the foil isberyllium with a thickness of about 50 microns. When the protonstraverse through the foil, energy of the protons is lost and the speedof the protons is reduced. Typically, a current is also generated,described infra. Protons moving at a slower speed travel in thesynchrotron with a reduced radius of curvature 266 compared to eitherthe original central beamline 264 or the altered circulating path 265.The reduced radius of curvature 266 path is also referred to herein as apath having a smaller diameter of trajectory or a path having protonswith reduced energy. The reduced radius of curvature 266 is typicallyabout two millimeters less than a radius of curvature of the last passof the protons along the altered proton beam path 265.

The thickness of the material 1230 is optionally adjusted to created achange in the radius of curvature, such as about ½, 1, 2, 3, or 4 mmless than the last pass of the protons 265 or original radius ofcurvature 264. Protons moving with the smaller radius of curvaturetravel between a second pair of blades. In one case, the second pair ofblades is physically distinct and/or are separated from the first pairof blades. In a second case, one of the first pair of blades is also amember of the second pair of blades. For example, the second pair ofblades is the second blade 1214 and a third blade 1216 in the RF cavitysystem 1210. A high voltage DC signal, such as about 1 to 5 kV, is thenapplied across the second pair of blades, which directs the protons outof the synchrotron through an extraction magnet 292, such as a Lambersonextraction magnet, into a transport path 268.

Control of acceleration of the charged particle beam path in thesynchrotron with the accelerator and/or applied fields of the turningmagnets in combination with the above described extraction system allowsfor control of the intensity of the extracted proton beam, whereintensity is a proton flux per unit time or the number of protonsextracted as a function of time. For example, when a current is measuredbeyond a threshold, the RF field modulation in the RF cavity system isterminated or reinitiated to establish a subsequent cycle of proton beamextraction. This process is repeated to yield many cycles of proton beamextraction from the synchrotron accelerator.

Because the extraction system does not depend on any change in magneticfield properties, it allows the synchrotron to continue to operate inacceleration or deceleration mode during the extraction process. Stateddifferently, the extraction process does not interfere with synchrotronacceleration. In stark contrast, traditional extraction systemsintroduce a new magnetic field, such as via a hexapole, during theextraction process. More particularly, traditional synchrotrons have amagnet, such as a hexapole magnet, that is off during an accelerationstage. During the extraction phase, the hexapole magnetic field isintroduced to the circulating path of the synchrotron. The introductionof the magnetic field necessitates two distinct modes, an accelerationmode and an extraction mode, which are mutually exclusive in time.

Charged Particle Beam Intensity Control

Control of applied field, such as a radio-frequency (RF) field,frequency and magnitude in the RF cavity system 1210 allows forintensity control of the extracted proton beam, where intensity isextracted proton flux per unit time or the number of protons extractedas a function of time.

Referring still to FIG. 12, when protons in the proton beam hit thematerial 1230 electrons are given off resulting in a current. Theresulting current is converted to a voltage and is used as part of a ionbeam intensity monitoring system or as part of an ion beam feedback loopfor controlling beam intensity. The voltage is optionally measured andsent to the main controller 110 or to a controller subsystem. Moreparticularly, when protons in the charged particle beam path passthrough the material 1230, some of the protons lose a small fraction oftheir energy, such as about one-tenth of a percent, which results in asecondary electron. That is, protons in the charged particle beam pushsome electrons when passing through material 1230 giving the electronsenough energy to cause secondary emission. The resulting electron flowresults in a current or signal that is proportional to the number ofprotons going through the target material 1230. The resulting current ispreferably converted to voltage and amplified. The resulting signal isreferred to as a measured intensity signal.

The amplified signal or measured intensity signal resulting from theprotons passing through the material 1230 is preferably used incontrolling the intensity of the extracted protons. For example, themeasured intensity signal is compared to a goal signal, which ispredetermined in an irradiation of the tumor plan 1260. In one example,the tumor plan 1260 contains the goal or targeted energy and intensityof the delivered proton beam as a function of x-position, y-position,time, and/or rotational position of the patient. The difference betweenthe measured intensity signal and the planned for goal signal iscalculated. The difference is used as a control to the RF generator.Hence, the measured flow of current resulting from the protons passingthrough the material 1230 is used as a control in the RF generator toincrease or decrease the number of protons undergoing betatronoscillation and striking the material 1230. Hence, the voltagedetermined off of the material 1230 is used as a measure of the orbitalpath and is used as a feedback control to control the RF cavity system.Alternatively, the measured intensity signal is not used in the feedbackcontrol and is just used as a monitor of the intensity of the extractedprotons.

As described, supra, the photons striking the material 1230 is a step inthe extraction of the protons from the synchrotron 130. Hence, themeasured intensity signal is used to change the number of protons perunit time being extracted, which is referred to as intensity of theproton beam. The intensity of the proton beam is thus under algorithmcontrol. Further, the intensity of the proton beam is controlledseparately from the velocity of the protons in the synchrotron 130.Hence, intensity of the protons extracted and the energy of the protonsextracted are independently variable.

For example, protons initially move at an equilibrium trajectory in thesynchrotron 130. An RF field is used to excite the protons into abetatron oscillation. In one case, the frequency of the protons orbit isabout 10 MHz. In one example, in about one millisecond or after about10,000 orbits, the first protons hit an outer edge of the targetmaterial 130. The specific frequency is dependent upon the period of theorbit. Upon hitting the material 130, the protons push electrons throughthe foil to produce a current. The current is converted to voltage andamplified to yield a measured intensity signal. The measured intensitysignal is used as a feedback input to control the applied RF magnitude,RF frequency, or RF field. Preferably, the measured intensity signal iscompared to a target signal and a measure of the difference between themeasured intensity signal and target signal is used to adjust theapplied RF field in the RF cavity system 1210 in the extraction systemto control the intensity of the protons in the extraction step. Statedagain, the signal resulting from the protons striking and/or passingthrough the material 130 is used as an input in RF field modulation. Anincrease in the magnitude of the RF modulation results in protonshitting the foil or material 130 sooner. By increasing the RF, moreprotons are pushed into the foil, which results in an increasedintensity, or more protons per unit time, of protons extracted from thesynchrotron 130.

In another example, a detector 1250 external to the synchrotron 130 isused to determine the flux of protons extracted from the synchrotron anda signal from the external detector is used to alter the RF field or RFmodulation in the RF cavity system 1210. Here the external detectorgenerates an external signal, which is used in a manner similar to themeasured intensity signal, described in the preceding paragraphs.Particularly, the measured intensity signal is compared to a desiredsignal from the irradiation plan 1260 in a feedback intensity controller1240, which adjusts the RF field between the first plate 1212 and thesecond plate 1214 in the extraction process, described supra.

In yet another example, when a current from material 130 resulting fromprotons passing through or hitting material is measured beyond athreshold, the RF field modulation in the RF cavity system is terminatedor reinitiated to establish a subsequent cycle of proton beamextraction. This process is repeated to yield many cycles of proton beamextraction from the synchrotron accelerator.

In still yet another embodiment, intensity modulation of the extractedproton beam is controlled by the main controller 110. The maincontroller 110 optionally and/or additionally controls timing ofextraction of the charged particle beam and energy of the extractedproton beam.

The benefits of the system include a multi-dimensional scanning system.Particularly, the system allows independence in: (1) energy of theprotons extracted and (2) intensity of the protons extracted. That is,energy of the protons extracted is controlled by an energy controlsystem and an intensity control system controls the intensity of theextracted protons. The energy control system and intensity controlsystem are optionally independently controlled. Preferably, the maincontroller 110 controls the energy control system and the maincontroller simultaneously controls the intensity control system to yieldan extracted proton beam with controlled energy and controlled intensitywhere the controlled energy and controlled intensity are independentlyvariable. Thus the irradiation spot hitting the tumor is underindependent control of:

-   -   time;    -   energy;    -   intensity;    -   x-axis position, where the x-axis represents horizontal movement        of the proton beam relative to the patient, and    -   y-axis position, where the y-axis represents vertical movement        of the proton beam relative to the patient.

In addition, the patient is optionally independently rotated relative toa translational axis of the proton beam at the same time. The system iscapable of pulse-to-pulse energy variability. Additionally, the systemis capable of dynamic energy modulation during a pulse, enabling truethree-dimensional proton beam scanning with energy and/or intensitymodulation.

Referring now to FIG. 13, a proton beam position verification system1300 is described. A nozzle 1310 provides an outlet for the secondreduced pressure vacuum system initiating at the foil 395 of the tandemaccelerator 390 and running through the synchrotron 130 to a nozzle foil1320 covering the end of the nozzle 1310. The nozzle expands incross-sectional area along the z-axis of the proton beam path 268 toallow the proton beam 268 to be scanned along the x- and y-axes by thevertical control element 142 and horizontal control element 144,respectively. The nozzle foil 1320 is preferably mechanically supportedby the outer edges of an exit port of the nozzle 1310. An example of anozzle foil or output foil 1320 is a sheet of about 0.1 inch thickaluminum foil. Generally, the nozzle foil separates atmosphere pressureson the patient side of the nozzle foil 1320 from the low pressureregion, such as about 10⁻⁵ to 10⁻⁷ torr region, on the synchrotron 130side of the nozzle foil 1320. The low pressure region is maintained toreduce scattering of the proton beam 264, 268.

Still referring to FIG. 13, the proton beam verification system 1300 isa system that allows for monitoring of the actual proton beam position268, 269 in real-time without destruction of the proton beam. The protonbeam verification system 1300 preferably includes a proton beam positionverification layer 1330, which is also referred to herein as a coating,luminescent, fluorescent, phosphorescent, radiance, or viewing layer.The verification layer or coating layer 1330 is preferably a coating orthin layer substantially in contact with an inside surface of the nozzlefoil or output foil 1320, where the inside surface is on the synchrotronside of the nozzle foil 1320. Less preferably, the verification layer orcoating layer 1330 is substantially in contact with an outer surface ofthe nozzle foil 1320, where the outer surface is on the patienttreatment side of the nozzle foil 1320. Preferably, the nozzle foil 1320provides a substrate surface for coating by the coating layer, butoptionally a separate coating layer support element, on which thecoating 1330 is mounted, is placed anywhere in the proton beam path 268.The coating layer preferably contains protons emitting centers ormolecular structures that emit photons when struck by charged particles,such as protons.

Still referring to FIG. 13, the coating 1330 yields a measurablespectroscopic response, spatially viewable by the detector 1340, as aresult of transmission by the proton beam 268. The coating 1330 ispreferably a phosphor, but is optionally any material that is viewableor imaged by a detector where the material changes spectroscopically asa result of the proton beam path 268 hitting or transmitting through thecoating 1330. For example, the coating 1330 emits photons when struck bycharged particles in the charged particle beam path. A detector orcamera 1340 views the coating layer 1330 and determines the currentposition of the proton beam 268 by the spectroscopic differencesresulting from protons passing through the coating layer. For example,the camera 1340 views the coating surface 1330 as the proton beam 268 isbeing scanned by the horizontal 144 and vertical 142 beam positioncontrol elements during treatment of the tumor 1420. The camera 1340views the current position of the proton beam 268 as measured byspectroscopic response. The coating layer 1330 is preferably a phosphoror luminescent material that glows or emits photons for a short periodof time, such as less than 5 seconds for a 50% intensity, as a result ofexcitation by the proton beam 268. Optionally, a plurality of cameras ordetectors 1340 are used, where each detector views all or a portion ofthe coating layer 1330. For example, two detectors 1340 are used where afirst detector views a first half of the coating layer and the seconddetector views a second half of the coating layer. Preferably, thedetector 1340 is mounted into the nozzle 1310 to view the proton beamposition after passing through the first axis and second axiscontrollers 142, 144. Preferably, the coating layer 1330 is positionedin the proton beam path 268 in a position prior to the protons strikingthe patient 1430.

Still referring to FIG. 13, the main controller 130, connected to thecamera or detector 1340 output, compares the actual proton beam position268 with the planned proton beam position and/or a calibration referenceto determine if the actual proton beam position 268 is within tolerance.The proton beam verification system 1300 preferably is used in at leasttwo phases, a calibration phase and a proton beam treatment phase. Thecalibration phase is used to correlate, as a function of x-, y-positionof the glowing response the actual x-, y-position of the proton beam atthe patient interface. During the proton beam treatment phase, theproton beam position is monitored and compared to the calibration and/ortreatment plan to verify accurate proton delivery to the tumor 1420and/or as a proton beam shutoff safety indicator.

Patient Positioning

Referring now to FIG. 14, the patient is preferably positioned on orwithin a patient positioning system 1410 of the patient interface module150. The patient positioning system 1410 is used to translate thepatient and/or rotate the patient into a zone where the proton beam canscan the tumor using a scanning system 140 or proton targeting system,described infra. Essentially, the patient positioning system 1410performs large movements of the patient to place the tumor near thecenter of a proton beam path 268 and the proton scanning or targetingsystem 140 performs fine movements of the momentary beam position 269 intargeting the tumor 1420. To illustrate, FIG. 14 shows the momentaryproton beam position 269 and a range of scannable positions 1440 usingthe proton scanning or targeting system 140, where the scannablepositions 1440 are about the tumor 1420 of the patient 1430. In thisexample, the scannable positions are scanned along the x- and y-axes;however, scanning is optionally simultaneously performed along thez-axis as described infra. This illustratively shows that the y-axismovement of the patient occurs on a scale of the body, such asadjustment of about 1, 2, 3, or 4 feet, while the scannable region ofthe proton beam 268 covers a portion of the body, such as a region ofabout 1, 2, 4, 6, 8, 10, or 12 inches. The patient positioning systemand its rotation and/or translation of the patient combines with theproton targeting system to yield precise and/or accurate delivery of theprotons to the tumor.

Referring still to FIG. 14, the patient positioning system 1410optionally includes a bottom unit 1412 and a top unit 1414, such asdiscs or a platform. Referring now to FIG. 14A, the patient positioningunit 1410 is preferably y-axis adjustable 1416 to allow verticalshifting of the patient relative to the proton therapy beam 268.Preferably, the vertical motion of the patient positioning unit 1410 isabout 10, 20, 30, or 50 centimeters per minute. Referring now to FIG.14B, the patient positioning unit 1410 is also preferably rotatable 1417about a rotation axis, such as about the y-axis running through thecenter of the bottom unit 1412 or about a y-axis running through thetumor 1420, to allow rotational control and positioning of the patientrelative to the proton beam path 268. Preferably the rotational motionof the patient positioning unit 1410 is about 360 degrees per minute.Optionally, the patient positioning unit rotates about 45, 90, or 180degrees. Optionally, the patient positioning unit 1410 rotates at a rateof about 45, 90, 180, 360, 720, or 1080 degrees per minute. The rotationof the positioning unit 1417 is illustrated about the rotation axis attwo distinct times, t₁ and t₂. Protons are optionally delivered to thetumor 1420 at n times where each of the n times represent differentdirections of the incident proton beam 269 hitting the patient 1430 dueto rotation of the patient 1417 about the rotation axis.

Any of the semi-vertical, sitting, or laying patient positioningembodiments described, infra, are optionally vertically translatablealong the y-axis or rotatable about the rotation or y-axis.

Preferably, the top and bottom units 1412, 1414 move together, such thatthey rotate at the same rates and translate in position at the samerates. Optionally, the top and bottom units 1412, 1414 are independentlyadjustable along the y-axis to allow a difference in distance betweenthe top and bottom units 1412, 1414. Motors, power supplies, andmechanical assemblies for moving the top and bottom units 1412, 1414 arepreferably located out of the proton beam path 269, such as below thebottom unit 1412 and/or above the top unit 1414. This is preferable asthe patient positioning unit 1410 is preferably rotatable about 360degrees and the motors, power supplies, and mechanical assembliesinterfere with the protons if positioned in the proton beam path 269

Proton Delivery Efficiency

Referring now to FIG. 15, a common distribution of relative doses forboth X-rays and proton irradiation is presented. As shown, X-raysdeposit their highest dose near the surface of the targeted tissue andthen exponentially decreases as function of tissue depth. The depositionof X-ray energy near the surface is non-ideal for tumors located deepwithin the body, which is usually the case, as excessive damage is doneto the soft tissue layers surrounding the tumor 1420. The advantage ofprotons is that they deposit most of their energy near the end of theflight trajectory as the energy loss per unit path of the absorbertransversed by a proton increases with decreasing particle velocity,giving rise to a sharp maximum in ionization near the end of the range,referred to herein as the Bragg peak. Furthermore, since the flighttrajectory of the protons is variable by increasing or decreasing theirinitial kinetic energy or initial velocity, then the peak correspondingto maximum energy is movable within the tissue. Thus z-axis control ofthe proton depth of penetration is allowed by theacceleration/extraction process, described supra. As a result of theprotons dose-distribution characteristics, a radiation oncologist canoptimize dosage to the tumor 1420 while minimizing dosage to surroundingnormal tissues.

The Bragg peak energy profile shows that protons deliver their energyacross the entire length of the body penetrated by the proton up to amaximum penetration depth. As a result, energy is being delivered, inthe distal portion of the Bragg peak energy profile, to healthy tissue,bone, and other body constituents before the proton beam hits the tumor.It follows that the shorter the pathlength in the body prior to thetumor, the higher the efficiency of proton delivery efficiency, whereproton delivery efficiency is a measure of how much energy is deliveredto the tumor relative to healthy portions of the patient. Examples ofproton delivery efficiency include: (1) a ratio of proton energydelivered to the tumor over proton energy delivered to non-tumor tissue;(2) pathlength of protons in the tumor versus pathlength in thenon-tumor tissue; and (3) damage to a tumor compared to damage tohealthy body parts. Any of these measures are optionally weighted bydamage to sensitive tissue, such as a nervous system element, heart,brain, or other organ. To illustrate, for a patient in a laying positionwhere the patient is rotated about the y-axis during treatment, a tumornear the heart would at times be treated with protons running throughthe head-to-heart path, leg-to-heart path, or hip-to-heart path, whichare all inefficient compared to a patient in a sitting or semi-verticalposition where the protons are all delivered through a shorterchest-to-heart; side-of-body-to-heart, or back-to-heart path.Particularly, compared to a laying position, using a sitting orsemi-vertical position of the patient, a shorter pathlength through thebody to a tumor is provided to a tumor located in the torso or head,which results in a higher or better proton delivery efficiency.

Herein proton delivery efficiency is separately described from the timeefficiency or synchrotron use efficiency, which is a fraction of timethat the charged particle beam apparatus is in operation.

Depth Targeting

Referring now to FIGS. 16 A-E, x-axis scanning of the proton beam isillustrated while z-axis energy of the proton beam undergoes controlledvariation 1600 to allow irradiation of slices of the tumor 1420. Forclarity of presentation, the simultaneous y-axis scanning that isperformed is not illustrated. In FIG. 16A, irradiation is commencingwith the momentary proton beam position 269 at the start of a firstslice. Referring now to FIG. 16B, the momentary proton beam position isat the end of the first slice. Importantly, during a given slice ofirradiation, the proton beam energy is preferably continuouslycontrolled and changed according to the tissue density in front of thetumor 1420. The variation of the proton beam energy to account fortissue density thus allows the beam stopping point, or Bragg peak, toremain inside the tissue slice. The variation of the proton beam energyduring scanning is possible due to the acceleration/extractiontechniques, described supra, which allow for acceleration of the protonbeam during extraction. FIGS. 16C, 16D, and 16E show the momentaryproton beam position in the middle of the second slice, two-thirds ofthe way through a third slice, and after finalizing irradiation from agiven direction, respectively. Using this approach, controlled,accurate, and precise delivery of proton irradiation energy to the tumor1420, to a designated tumor subsection, or to a tumor layer is achieved.Efficiency of deposition of proton energy to tumor, as defined as theratio of the proton irradiation energy delivered to the tumor relativeto the proton irradiation energy delivered to the healthy tissue isfurther described infra.

Multi-Field Irradiation

It is desirable to maximize efficiency of deposition of protons to thetumor 1420, as defined by maximizing the ratio of the proton irradiationenergy delivered to the tumor 1420 relative to the proton irradiationenergy delivered to the healthy tissue. Irradiation from one, two, orthree directions into the body, such as by rotating the body about 90degrees between irradiation sub-sessions results in proton irradiationfrom the distal portion of the Bragg peak concentrating into one, two,or three healthy tissue volumes, respectively. It is desirable tofurther distribute the distal portion of the Bragg peak energy evenlythrough the healthy volume tissue surrounding the tumor 1420.

Multi-field irradiation is proton beam irradiation from a plurality ofentry points into the body. For example, the patient 1430 is rotated andthe radiation source point is held constant. For example, as the patient1430 is rotated through 360 degrees and proton therapy is applied from amultitude of angles resulting in the distal radiation beingcircumferentially spread about the tumor yielding enhanced protonirradiation efficiency. In one case, the body is rotated into greaterthan 3, 5, 10, 15, 20, 25, 30, or 35 positions and proton irradiationoccurs with each rotation position. Rotation of the patient for protontherapy or for X-ray imaging is preferably about 45, 90, 135, 180, 270,or 360 degrees. Rotation of the patient is preferably performed usingthe patient positioning system 1410 and/or the bottom unit 1412 or disc,described supra. Rotation of the patient 1430 while keeping the deliveryproton beam 268 in a relatively fixed orientation allows irradiation ofthe tumor 1420 from multiple directions without use of a new collimatorfor each direction. Further, as no new setup is required for eachrotation position of the patient 1430, the system allows the tumor 1420to be treated from multiple directions without reseating or positioningthe patient, thereby minimizing tumor 1420 regeneration time andincreasing patient 1430 cancer therapy throughput.

The patient is optionally centered on the bottom unit 1412 or the tumor1420 is optionally centered on the bottom unit 1412. If the patient iscentered on the bottom unit 1412, then the first axis control element142 and second axis control element 144 are programmed to compensate forthe off central axis of rotation position variation of the tumor 1420.

Referring now to FIGS. 17 A-E, an example of multi-field irradiation1700 is presented. In this example, five patient rotation positions areillustrated; however, the five rotation positions are discrete rotationpositions of about thirty-six rotation positions, where the body isrotated about ten degrees with each position. Referring now to FIG. 17A,a range of irradiation beam positions 269 is illustrated from a firstbody rotation position, illustrated as the patient 1430 facing theproton irradiation beam where a first healthy volume 1711 is irradiatedby the ingress or distal portion of the Bragg peak energy irradiationprofile. Referring now to FIG. 17B, the patient 1430 is rotated aboutforty degrees and the irradiation is repeated. In the second position,the tumor 1420 again receives the bulk of the irradiation energy and asecond healthy tissue volume 1712 receives the smaller ingress or distalportion of the Bragg peak energy. Referring now to FIGS. 17 C-E, thepatient 1430 is rotated a total of about 90, 130, and 180 degrees,respectively. For each of the third, fourth, and fifth rotationpositions, the tumor 1420 receives the bulk of the irradiation energyand the third 1713, fourth 1714, and fifth 1715 healthy tissue volumesreceive the smaller ingress or distal portion of the Bragg peak energy,respectively. Thus, the rotation of the patient during proton therapyresults in the distal energy of the delivered proton energy to bedistributed about the tumor 1420, such as to regions one to five, whilealong a given axis, at least about 75, 80, 85, 90, or 95 percent of theenergy is delivered to the tumor 1420.

For a given rotation position, all or part of the tumor is irradiated.For example, in one embodiment only a distal section or distal slice ofthe tumor 1420 is irradiated with each rotation position, where thedistal section is a section furthest from the entry point of the protonbeam into the patient 1430. For example, the distal section is thedorsal side of the tumor when the patient 1430 is facing the proton beamand the distal section is the ventral side of the tumor when the patient1430 is facing away from the proton beam.

Referring now to FIG. 18, a second example of multi-field irradiation1800 is presented where the proton source is stationary and the patient1430 is rotated. For ease of presentation, the proton beam path 269 isillustrated as entering the patient 1430 from varying sides at times t₁,t₂, t₃, . . . , t_(n), t_(n+1). At a first time, t₁, the distal end ofthe Bragg peak profile hits a first area 1810, A₁. The patient isrotated and the proton beam path is illustrated at a second time, t₂,where the distal end of the Bragg peak hits a second area 1820, A₂. At athird time, the distal end of the Bragg peak profile hits a third area1830, A₃. This rotation and irradiation process is repeated n times,where n is a positive number greater than four and preferably greaterthan about 10, 20, 30, 100, or 300. At an n^(th) time the distal end ofthe Bragg peak profile strikes an n^(th) area 1840. As illustrated, atan n^(th) time, t_(n), if the patient 1430 is rotated further, theproton beam would hit a sensitive body constituent 1450, such as thespinal cord or eyes. Irradiation is preferably suspended until thesensitive body constituent is rotated out of the proton beam path.Irradiation is resumed at a time, t_(n+1), after the sensitive bodyconstituent 1450 is rotated our of the proton beam path. At time t_(n+1)the Bragg peak distal energy strikes a t_(n+1) area 1450. In thismanner, the Bragg peak energy is always within the tumor, the distalregion of the Bragg peak profile is distributed in healthy tissue aboutthe tumor 1420, and sensitive body constituents 1450 receive minimal orno proton beam irradiation.

In one multi-field irradiation example, the particle therapy system witha synchrotron ring diameter of less than six meters includes ability to:

-   -   rotate the patient through about 360 degrees;    -   extract radiation in about 0.1 to 10 seconds;    -   scan vertically about 100 millimeters;    -   scan horizontally about 700 millimeters;    -   vary beam energy from about 30 to 330 MeV/second during        irradiation;    -   focus the proton beam from about 2 to 20 millimeters at the        tumor; and/or    -   complete multi-field irradiation of a tumor in less than about        1, 2, 4, or 6 minutes as measured from the time of initiating        proton delivery to the patient 1430.

Referring now to FIG. 19, two multi-field irradiation methods 1900 aredescribed. In the first method, the main controller 110 rotationallypositions 1910 the patient 1430 and subsequently irradiates 1920 thetumor 1420. The process is repeated until a multi-field irradiation planis complete. In the second method, the main controller 110simultaneously rotates and irradiates 1930 the tumor 1420 within thepatient 1430 until the multi-field irradiation plan is complete. Moreparticularly, the proton beam irradiation occurs while the patient 1430is being rotated.

The 3-dimensional scanning system of the proton spot focal point,described herein, is preferably combined with a rotation/raster method.The method includes layer wise tumor irradiation from many directions.During a given irradiation slice, the proton beam energy is continuouslychanged according to the tissue's density in front of the tumor toresult in the beam stopping point, defined by the Bragg peak, to alwaysbe inside the tumor and inside the irradiated slice. The novel methodallows for irradiation from many directions, referred to herein asmulti-field irradiation, to achieve the maximal effective dose at thetumor level while simultaneously significantly reducing possibleside-effects on the surrounding healthy tissues in comparison withexisting methods. Essentially, the multi-field irradiation systemdistributes dose-distribution at tissue depths not yet reaching thetumor.

Proton Beam Position Control

Referring now to FIG. 20, a beam delivery and tissue volume scanningsystem is illustrated. Presently, the worldwide radiotherapy communityuses a method of dose field forming using a pencil beam scanning system.In stark contrast, FIG. 20 illustrates a spot scanning system or tissuevolume scanning system. In the tissue volume scanning system, the protonbeam is controlled, in terms of transportation and distribution, usingan inexpensive and precise scanning system. The scanning system is anactive system, where the beam is focused into a spot focal point ofabout one-half, one, two, or three millimeters in diameter. The focalpoint is translated along two axes while simultaneously altering theapplied energy of the proton beam, which effectively changes the thirddimension of the focal point. The system is applicable in combinationwith the above described rotation of the body, which preferably occursin-between individual moments or cycles of proton delivery to the tumor.Optionally, the rotation of the body by the above described systemoccurs continuously and simultaneously with proton delivery to thetumor.

For example, in the illustrated system in FIG. 20A, the spot istranslated horizontally, is moved down a vertical y-axis, and is thenback along the horizontal axis. In this example, current is used tocontrol a vertical scanning system having at least one magnet. Theapplied current alters the magnetic field of the vertical scanningsystem to control the vertical deflection of the proton beam. Similarly,a horizontal scanning magnet system controls the horizontal deflectionof the proton beam. The degree of transport along each axes iscontrolled to conform to the tumor cross-section at the given depth. Thedepth is controlled by changing the energy of the proton beam. Forexample, the proton beam energy is decreased, so as to define a newpenetration depth, and the scanning process is repeated along thehorizontal and vertical axes covering a new cross-sectional area of thetumor. Combined, the three axes of control allow scanning or movement ofthe proton beam focal point over the entire volume of the canceroustumor. The time at each spot and the direction into the body for eachspot is controlled to yield the desired radiation does at eachsub-volume of the cancerous volume while distributing energy hittingoutside of the tumor.

The focused beam spot volume dimension is preferably tightly controlledto a diameter of about 0.5, 1, or 2 millimeters, but is alternativelyseveral centimeters in diameter. Preferred design controls allowscanning in two directions with: (1) a vertical amplitude of about 100mm amplitude and frequency up to about 200 Hz; and (2) a horizontalamplitude of about 700 mm amplitude and frequency up to about 1 Hz.

In FIG. 27A, the proton beam is illustrated along a z-axis controlled bythe beam energy, the horizontal movement is along an x-axis, and thevertical direction is along a y-axis. The distance the protons movealong the z-axis into the tissue, in this example, is controlled by thekinetic energy of the proton. This coordinate system is arbitrary andexemplary. The actual control of the proton beam is controlled in3-dimensional space using two scanning magnet systems and by controllingthe kinetic energy of the proton beam. The use of the extraction system,described supra, allows for different scanning patterns. Particularly,the system allows simultaneous adjustment of the x-, y-, and z-axes inthe irradiation of the solid tumor. Stated again, instead of scanningalong an x,y-plane and then adjusting energy of the protons, such aswith a range modulation wheel, the system allows for moving along thez-axes while simultaneously adjusting the x- and or y-axes. Hence,rather than irradiating slices of the tumor, the tumor is optionallyirradiated in three simultaneous dimensions. For example, the tumor isirradiated around an outer edge of the tumor in three dimensions. Thenthe tumor is irradiated around an outer edge of an internal section ofthe tumor. This process is repeated until the entire tumor isirradiated. The outer edge irradiation is preferably coupled withsimultaneous rotation of the subject, such as about a vertical y-axis.This system allows for maximum efficiency of deposition of protons tothe tumor, as defined as the ratio of the proton irradiation energydelivered to the tumor relative to the proton irradiation energydelivered to the healthy tissue.

Combined, the system allows for multi-axes control of the chargedparticle beam system in a small space with low power supply. Forexample, the system uses multiple magnets where each magnet has at leastone edge focusing effect in each turning section of the synchrotronand/or multiple magnets having concentrating magnetic field geometry, asdescribed supra. The multiple edge focusing effects in the circulatingbeam path of the synchrotron combined with the concentration geometry ofthe magnets and described extraction system yields a synchrotron having:

-   -   a small circumference system, such as less than about 50 meters;    -   a vertical proton beam size gap of about 2 cm;    -   corresponding reduced power supply requirements associated with        the reduced gap size;    -   an extraction system not requiring a newly introduced magnetic        field;    -   acceleration or deceleration of the protons during extraction;        and    -   control of z-axis energy during extraction.

The result is a 3-dimensional scanning system, x-, y-, and z-axescontrol, where the z-axes control resides in the synchrotron and wherethe z-axes energy is variably controlled during the extraction processinside the synchrotron.

Referring now to FIG. 27B, an example of a proton scanning or targetingsystem 140 used to direct the protons to the tumor with 4-dimensionalscanning control is provided, where the 4-dimensional scanning controlis along the x-, y-, and z-axes along with intensity control, asdescribed supra. A fifth axis is time. Typically, charged particlestraveling along the transport path 268 are directed through a first axiscontrol element 142, such as a vertical control, and a second axiscontrol element 144, such as a horizontal control and into a tumor 1420.As described, supra, the extraction system also allows for simultaneousvariation in the z-axis. Further, as describe, supra, the intensity ordose of the extracted beam is optionally simultaneously andindependently controlled and varied. Thus instead of irradiating a sliceof the tumor, as in FIG. 27A, all four dimensions defining the targetingspot of the proton delivery in the tumor are simultaneously variable.The simultaneous variation of the proton delivery spot is illustrated inFIG. 27B by the spot delivery path 269. In the illustrated case, theprotons are initially directed around an outer edge of the tumor and arethen directed around an inner radius of the tumor. Combined withrotation of the subject about a vertical axis, a multi-fieldillumination process is used where a not yet irradiated portion of thetumor is preferably irradiated at the further distance of the tumor fromthe proton entry point into the body. This yields the greatestpercentage of the proton delivery, as defined by the Bragg peak, intothe tumor and minimizes damage to peripheral healthy tissue.

Imaging/X-Ray System

Herein, an X-ray system is used to illustrate an imaging system.

Timing

An X-ray is preferably collected either (1) just before or (2)concurrently with treating a subject with proton therapy for a couple ofreasons. First, movement of the body, described supra, changes the localposition of the tumor in the body relative to other body constituents.If the subject has an X-ray taken and is then bodily moved to a protontreatment room, accurate alignment of the proton beam to the tumor isproblematic. Alignment of the proton beam to the tumor using one or moreX-rays is best performed at the time of proton delivery or in theseconds or minutes immediately prior to proton delivery and after thepatient is placed into a therapeutic body position, which is typically afixed position or partially immobilized position. Second, the X-raytaken after positioning the patient is used for verification of protonbeam alignment to a targeted position, such as a tumor and/or internalorgan position.

Positioning

An X-ray is preferably taken just before treating the subject to aid inpatient positioning. For positioning purposes, an X-ray of a large bodyarea is not needed. In one embodiment, an X-ray of only a local area iscollected. When collecting an X-ray, the X-ray has an X-ray path. Theproton beam has a proton beam path. Overlaying the X-ray path with theproton beam path is one method of aligning the proton beam to the tumor.However, this method involves putting the X-ray equipment into theproton beam path, taking the X-ray, and then moving the X-ray equipmentout of the beam path. This process takes time. The elapsed time whilethe X-ray equipment moves has a couple of detrimental effects. First,during the time required to move the X-ray equipment, the body moves.The resulting movement decreases precision and/or accuracy of subsequentproton beam alignment to the tumor. Second, the time required to movethe X-ray equipment is time that the proton beam therapy system is notin use, which decreases the total efficiency of the proton beam therapysystem.

X-Ray Source Lifetime

Preferably, components in the particle beam therapy system requireminimal or no maintenance over the lifetime of the particle beam therapysystem. For example, it is desirable to equip the proton beam therapysystem with an X-ray system having a long lifetime source, such as alifetime of about 20 years.

In one system, described infra, electrons are used to create X-rays. Theelectrons are generated at a cathode where the lifetime of the cathodeis temperature dependent. Analogous to a light bulb, where the filamentis kept in equilibrium, the cathode temperature is held in equilibriumat temperatures at about 200, 500, or 1000 degrees Celsius. Reduction ofthe cathode temperature results in increased lifetime of the cathode.Hence, the cathode used in generating the electrons is preferably heldat as low of a temperature as possible. However, if the temperature ofthe cathode is reduced, then electron emissions also decrease. Toovercome the need for more electrons at lower temperatures, a largecathode is used and the generated electrons are concentrated. Theprocess is analogous to compressing electrons in an electron gun;however, here the compression techniques are adapted to apply toenhancing an X-ray tube lifetime.

Referring now to FIG. 21, an example of an X-ray generation device 2100having an enhanced lifetime is provided. Electrons 2120 are generated ata cathode 2110, focused with a control electrode 2112, and acceleratedwith a series of accelerating electrodes 2140. The accelerated electrons2150 impact an X-ray generation source 2148 resulting in generatedX-rays that are then directed along an X-ray path 2270 to the subject1430. The concentrating of the electrons from a first diameter 2115 to asecond diameter 2116 allows the cathode to operate at a reducedtemperature and still yield the necessary amplified level of electronsat the X-ray generation source 2148. In one example, the X-raygeneration source is the anode coupled with the cathode 2110 and/or theX-ray generation source is substantially composed of tungsten.

Still referring to FIG. 21, a more detailed description of an exemplaryX-ray generation device 2100 is described. An anode 2114/cathode 2110pair is used to generated electrons. The electrons 2120 are generated atthe cathode 2110 having a first diameter 2115, which is denoted d₁. Thecontrol electrodes 2112 attract the generated electrons 2120. Forexample, if the cathode is held at about −150 kV and the controlelectrode is held at about −149 kV, then the generated electrons 2120are attracted toward the control electrodes 2112 and focused. A seriesof accelerating electrodes 2140 are then used to accelerate theelectrons into a substantially parallel path 2150 with a smallerdiameter 2116, which is denoted d₂. For example, with the cathode heldat −150 kV, a first, second, third, and fourth accelerating electrodes2142, 2144, 2146, 2148 are held at about −120, −90, −60, and −30 kV,respectively. If a thinner body part is to be analyzed, then the cathode2110 is held at a smaller level, such as about −90 kV and the controlelectrode, first, second, third, and fourth electrode are each adjustedto lower levels. Generally, the voltage difference from the cathode tofourth electrode is less for a smaller negative voltage at the cathodeand vise-versa. The accelerated electrons 2150 are optionally passedthrough a magnetic lens 2160 for adjustment of beam size, such as acylindrical magnetic lens. The electrons are also optionally focusedusing quadrupole magnets 2170, which focus in one direction and defocusin another direction. The accelerated electrons 2150, which are nowadjusted in beam size and focused strike an X-ray generation source2148, such as tungsten, resulting in generated X-rays that pass througha blocker 2262 and proceed along an X-ray path 2170 to the subject. TheX-ray generation source 2148 is optionally cooled with a cooling element2149, such as water touching or thermally connected to a backside of theX-ray generation source 2148. The concentrating of the electrons from afirst diameter 2115 to a second diameter 2116 allows the cathode tooperate at a reduced temperature and still yield the necessary amplifiedlevel of electrons at the X-ray generation source 2148.

More generally, the X-ray generation device 2100 produces electronshaving initial vectors. One or more of the control electrode 2112,accelerating electrodes 2140, magnetic lens 2160, and quadrupole magnets2170 combine to alter the initial electron vectors into parallel vectorswith a decreased cross-sectional area having a substantially parallelpath, referred to as the accelerated electrons 2150. The process allowsthe X-ray generation device 2100 to operate at a lower temperature.Particularly, instead of using a cathode that is the size of theelectron beam needed, a larger electrode is used and the resultingelectrons 2120 are focused and/or concentrated into the requiredelectron beam needed. As lifetime is roughly an inverse of currentdensity, the concentration of the current density results in a largerlifetime of the X-ray generation device. A specific example is providedfor clarity. If the cathode has a fifteen mm radius or d₁ is about 30mm, then the area (πr²) is about 225 mm² times pi. If the concentrationof the electrons achieves a radius of five mm or d₂ is about 10 mm, thenthe area (πr²) is about 25 mm² times pi. The ratio of the two areas isabout nine (225π/25π). Thus, there is about nine times less density ofcurrent at the larger cathode compared to the traditional cathode havingan area of the desired electron beam. Hence, the lifetime of the largercathode approximates nine times the lifetime of the traditional cathode,though the actual current through the larger cathode and traditionalcathode is about the same. Preferably, the area of the cathode 2110 isabout 2, 4, 6, 8, 10, 15, 20, or 25 times that of the cross-sectionalarea of the substantially parallel electron beam 2150.

In another embodiment of the invention, the quadrupole magnets 2170result in an oblong cross-sectional shape of the electron beam 2150. Aprojection of the oblong cross-sectional shape of the electron beam 2150onto the X-ray generation source 2148 results in an X-ray beam that hasa small spot in cross-sectional view, which is preferably substantiallycircular in cross-sectional shape, that is then passed through thepatient 2130. The small spot is used to yield an X-ray having enhancedresolution at the patient.

Referring now to FIG. 22, in one embodiment, an X-ray is generated closeto, but not in, the proton beam path. A proton beam therapy system andan X-ray system combination 2200 is illustrated in FIG. 22. The protonbeam therapy system has a proton beam 268 in a transport system afterthe Lamberson extraction magnet 292 of the synchrotron 130. The protonbeam is directed by the scanning/targeting/delivery system 140 to atumor 1420 of a patient 1430. The X-ray system 2205 includes an electronbeam source 2105 generating an electron beam 2150. The electron beam isdirected to an X-ray generation source 2148, such as a piece oftungsten. Preferably, the tungsten X-ray source is located about 1, 2,3, 5, 10, 15, 20, or 40 millimeters from the proton beam path 268. Whenthe electron beam 2150 hits the tungsten, X-rays are generated in alldirections. X-rays are blocked with a port 2262 and are selected for anX-ray beam path 2270. The X-ray beam path 2270 and proton beam path 268run substantially in parallel as they progress to the tumor 1420. Thedistance between the X-ray beam path 2270 and proton beam path 269preferably diminishes to near zero and/or the X-ray beam path 2270 andproton beam path 269 overlap by the time they reach the tumor 1420.Simple geometry shows this to be the case given the long distance, of atleast a meter, between the tungsten and the tumor 1420. The distance isillustrated as a gap 2280 in FIG. 22. The X-rays are detected at anX-ray detector 2290, which is used to form an image of the tumor 1420and/or position of the patient 1430.

As a whole, the system generates an X-ray beam that lies insubstantially the same path as the proton therapy beam. The X-ray beamis generated by striking a tungsten or equivalent material with anelectron beam. The X-ray generation source is located proximate to theproton beam path. Geometry of the incident electrons, geometry of theX-ray generation material, and geometry of the X-ray beam blocker 262yield an X-ray beam that runs either in substantially in parallel withthe proton beam or results in an X-ray beam path that starts proximatethe proton beam path an expands to cover and transmit through a tumorcross-sectional area to strike an X-ray detector array or film allowingimaging of the tumor from a direction and alignment of the protontherapy beam. The X-ray image is then used to control the chargedparticle beam path to accurately and precisely target the tumor, and/oris used in system verification and validation.

Having an X-ray generation source 2148 that is proximate the proton beampath 268 allows for an X-ray of the patient 1430 to be collected closein time to use of the proton beam for tumor 1420 therapy as the X-raygeneration source 2148 need not be mechanically moved prior to protontherapy. For instance, proton irradiation of the tumor 1420 occurswithin about 1, 5, 10, 20, 30, or 60 seconds of when the X-ray iscollected.

Referring now to FIG. 23, additional geometry of the electron beam path2150 and X-ray beam path 2270 is illustrated. Particularly, the electronbeam 350 is shown as an expanded electron beam path 2152, 2154. Also,the X-ray beam path 2270 is shown as an expanded X-ray beam path 2272,2274.

Referring now to FIG. 24, a 3-dimensional (3-D) X-ray tomography system2400 is presented. In a typical X-ray tomography system, the X-raysource and detector rotationally translate about a stationary subject.In the X-ray tomography system described herein, the X-ray source anddetector are stationary and the patient 1430 rotates. The stationaryX-ray source allows a system where the X-ray source 2148 is proximatethe proton therapy beam path 268, as described supra. In addition, therotation of the patient 1430 allows the proton dosage and/or X-ray to bedistributed around the body, rather than being concentrated on onestatic entrance side of the body. Further, the 3-D X-ray tomographysystem allows for simultaneous updates of the tumor position relative tobody constituents in real-time during proton therapy treatment of thetumor 1420 in the patient 1430. The X-ray tomography system is furtherdescribed, infra.

In a first step of the X-ray tomography system 2400, the patient 1430 ispositioned relative to the X-ray beam path 2270 and proton beam path 268using a patient semi-immobilization/placement system, described infra.After patient 1430 positioning, a series of reference 2-D X-ray imagesare collected, on a detector array 2290 or film, of the patient 1430 andtumor 1420 as the subject is rotated about a y-axis 1417. For example, aseries of about 50, 100, 200, or 400 X-ray images of the patient arecollected as the patient is rotated. In a second example, an X-ray imageis collected with each n degrees of rotation of the patient 1430, wheren is about ½, 1, 2, 3, or 5 degrees of rotation. Preferably, about 200images are collected during one full rotation of the patient through 360degrees. Subsequently, using the reference 2-D X-ray images, analgorithm produces a reference 3-D picture of the tumor 1420 relative tothe patient's constituent body parts. A tumor 1420 irradiation plan ismade using the 3-D picture of the tumor 1420 and the patient'sconstituent body parts. Creation of the proton irradiation plan isoptionally performed after the patient has moved from the X-ray imagingarea.

In a second step, the patient 1430 is repositioned relative to the X-raybeam path 2270 and proton beam path 268 using the patientsemi-immobilization/placement system. Just prior to implementation ofthe proton irradiation plan, a few comparative X-ray images of thepatient 1430 and tumor 1420 are collected at a limited number ofpositions using the X-ray tomography system 2400 setup. For example, asingle X-ray image is collected with the patient positioned straight on,at angles of plus/minus forty-five degrees, and/or at angles ofplus/minus ninety degrees relative to the proton beam path 268. Theactual orientation of the patient 1430 relative to the proton beam path268 is optionally any orientation. The actual number of comparativeX-ray images is also optionally any number of images, though thepreferable number of comparative X-ray images is about 2 to 5comparative images. The comparative X-ray images are compared to thereference X-ray images and differences are detected. A medical expert oran algorithm determines if the difference between the reference imagesand the comparative images is significant. Based upon the differences,the medical expert or algorithm determines if: proton treatment shouldcommence, be halted, or adapted in real-time. For example, ifsignificant differences in the X-ray images are observed, then thetreatment is preferably halted and the process of collecting a reference3-D picture of the patient's tumor is reinitiated. In a second example,if the differences in the X-ray images are observed to be small, thenthe proton irradiation plan commences. In a third example, the algorithmor medical expert can adapt the proton irradiation plan in real-time toadjust for differences in tumor location resulting from changes inposition of the tumor 1420 in the patient 1430 or from differences inthe patient 1430 placement. In the third example, the adaptive protontherapy increases patient throughput and enhances precision and accuracyof proton irradiation of the tumor 1420 relative to the healthy tissueof the patient 1430.

Patient Immobilization

Accurate and precise delivery of a proton beam to a tumor of a patientrequires: (1) positioning control of the proton beam and (2) positioningcontrol of the patient. As described, supra, the proton beam iscontrolled using algorithms and magnetic fields to a diameter of about0.5, 1, or 2 millimeters. This section addresses partial immobilization,restraint, and/or alignment of the patient to insure the tightlycontrolled proton beam efficiently hits a target tumor and notsurrounding healthy tissue as a result of patient movement.

In this section an x-, y-, and z-axes coordinate system and rotationaxis is used to describe the orientation of the patient relative to theproton beam. The z-axis represent travel of the proton beam, such as thedepth of the proton beam into the patient. When looking at the patientdown the z-axis of travel of the proton beam, the x-axis refers tomoving left or right across the patient and the y-axis refers tomovement up or down the patient. A first rotation axis is rotation ofthe patient about the y-axis and is referred to herein as a rotationaxis, bottom unit 1412 rotation axis, or y-axis of rotation. Inaddition, tilt is rotation about the x-axis, yaw is rotation about they-axis, and roll is rotation about the z-axis. In this coordinatesystem, the proton beam path 269 optionally runs in any direction. As anillustrative matter, the proton beam path running through a treatmentroom is described as running horizontally through the treatment room.

In this section, a semi-vertical partial immobilization system 2500 isdescribed, which is also illustrative of a sitting partialimmobilization system or a laying positioning system.

Vertical Patient Positioning/Immobilization

Referring now to FIG. 25, the semi-vertical patient positioning system2500 is preferably used in conjunction with proton therapy of tumors inthe torso. The patient positioning and/or immobilization system controlsand/or restricts movement of the patient during proton beam therapy. Ina first partial immobilization embodiment, the patient is positioned ina semi-vertical position in a proton beam therapy system. Asillustrated, the patient is reclining at an angle alpha, α, about 45degrees off of the y-axis as defined by an axis running from head tofoot of the patient. More generally, the patient is optionallycompletely standing in a vertical position of zero degrees off the ofy-axis or is in a semi-vertical position alpha that is reclined about 5,10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, or 65 degrees off of they-axis toward the z-axis.

Patient positioning constraints 2515 are used to maintain the patient ina treatment position, including one or more of: a seat support 2520, aback support 2530, a head support 2540, an arm support 2550, a kneesupport 2560, and a foot support 2570. The constraints are optionallyand independently rigid or semi-rigid. Examples of a semi-rigid materialinclude a high or low density foam or a visco-elastic foam. For examplethe foot support is preferably rigid and the back support is preferablysemi-rigid, such as a high density foam material. One or more of thepositioning constraints 2515 are movable and/or under computer controlfor rapid positioning and/or immobilization of the patient. For example,the seat support 2520 is adjustable along a seat adjustment axis 2522,which is preferably the y-axis; the back support 2530 is adjustablealong a back support axis 2532, which is preferably dominated by z-axismovement with a y-axis element; the head support 2540 is adjustablealong a head support axis 2542, which is preferably dominated by z-axismovement with a y-axis element; the arm support 2550 is adjustable alongan arm support axis 2552, which is preferably dominated by z-axismovement with a y-axis element; the knee support 2560 is adjustablealong a knee support axis 2562, which is preferably dominated by y-axismovement with a z-axis element; and the foot support 2570 is adjustablealong a foot support axis 2572, which is preferably dominated by y-axismovement with a z-axis element.

If the patient is not facing the incoming proton beam, then thedescription of movements of support elements along the axes change, butthe immobilization elements are the same.

An optional camera 2580 is used with the patient immobilization system.The camera views the patient/subject creating an video image. The imageis provided to one or more operators of the charged particle beam systemand allows the operators a safety mechanism for determining if thesubject has moved or desires to terminate the proton therapy treatmentprocedure. Based on the video image, the operators may suspend orterminate the proton therapy procedure. For example, if the operatorobserves via the video image that the subject is moving, then theoperator has the option to terminate or suspend the proton therapyprocedure.

An optional video display 2590 is provided to the patient. The videodisplay optionally presents to the patient any of: operatorinstructions, system instructions, status of treatment, orentertainment.

Motors for positioning the constraints 2515, the camera 2580, and videodisplay 2590 are preferably mounted above or below the proton path.

Respiration control is optionally performed by using the video display.As the patient breathes, internal and external structures of the bodymove in both absolute terms and in relative terms. For example, theoutside of the chest cavity and internal organs both have absolute moveswith a breath. In addition, the relative position of an internal organrelative to another body component, such as an outer region of the body,a bone, support structure, or another organ, moves with each breath.Hence, for more accurate and precise tumor targeting, the proton beam ispreferably delivered at point a in time where the position of theinternal structure or tumor is well defined, such as at the bottom ofeach breath. The video display is used to help coordinate the protonbeam delivery with the patient's breathing cycle. For example, the videodisplay optionally displays to the patient a command, such as a holdbreath statement, a breath statement, a countdown indicating when abreadth will next need to be held, or a countdown until breathing mayresume.

The semi-vertical patient positioning system 2500 and sitting patientpositioning system are preferentially used to treatment of tumors in thehead or torso due to efficiency. The semi-vertical patient positioningsystem 2500, sitting patient positioning system, and laying patientpositioning system are all usable for treatment of tumors in thepatient's limbs.

Support System Elements

Positioning constraints 2515 include all elements used to position thepatient, such as those described in the semi-vertical positioning system2500, sitting positioning system, and laying positioning system.Preferably, positioning constraints or support system elements arealigned in positions that do not impede or overlap the proton beam path269. However, in some instances the positioning constraints are in theproton beam path 269 during at least part of the time of treatment ofthe patient. For instance, a positioning constraint element may residein the proton beam path 269 during part of a time period where thepatient is rotated about the y-axis during treatment. In cases or timeperiods that the positioning constraints or support system elements arein the proton beam path, then an upward adjustment of proton beam energyis preferably applied that increases the proton beam energy to offsetthe positioning constraint element impedance of the proton beam. In onecase, the proton beam energy is increased by a separate measure of thepositioning constraint element impedance determined during a referencescan of the positioning constraint system element or set of referencescans of the positioning constraint element as a function of rotationabout the y-axis.

For clarity, the positioning constraints 2515 or support system elementsare herein described relative to the semi-vertical positioning system2500; however, the positioning elements and descriptive x-, y-, andz-axes are adjustable to fit any coordinate system, to the sittingpositioning system, or the laying positioning system.

An example of a head support system is described to support, align,and/or restrict movement of a human head. The head support systempreferably has several head support elements including any of: a back ofhead support, a right of head alignment element, and a left of headalignment element. The back of head support element is preferably curvedto fit the head and is optionally adjustable along a head support axis,such as along the z-axis. Further, the head supports, like the otherpatient positioning constraints, is preferably made of a semi-rigidmaterial, such as a low or high density foam, and has an optionalcovering, such as a plastic or leather. The right of head alignmentelement and left of head alignment elements or head alignment elements,are primarily used to semi-constrain movement of the head. The headalignment elements are preferably padded and flat, but optionally have aradius of curvature to fit the side of the head. The right and left headalignment elements are preferably respectively movable along translationaxes to make contact with the sides of the head. Restricted movement ofthe head during proton therapy is important when targeting and treatingtumors in the head or neck. The head alignment elements and the back ofhead support element combine to restrict tilt, rotation or yaw, rolland/or position of the head in the x-, y-, z-axes coordinate system.

Positioning System Computer Control

One or more of the patient positioning unit components and/or one ofmore of the patient positioning constraints are preferably undercomputer control, where the computer control positioning devices, suchas via a series of motors and drives, to reproducibly position thepatient. For example, the patient is initially positioned andconstrained by the patient positioning constraints. The position of eachof the patient positioning constraints is recorded and saved by the maincontroller 110, by a sub-controller or the main controller 110, or by aseparate computer controller. Then, medical devices are used to locatethe tumor 1420 in the patient 1430 while the patient is in theorientation of final treatment. The imaging system 170 includes one ormore of: MRI's, X-rays, CT's, proton beam tomography, and the like. Timeoptionally passes at this point where images from the imaging system 170are analyzed and a proton therapy treatment plan is devised. The patientmay exit the constraint system during this time period, which may beminutes, hours, or days. Upon return of the patient to the patientpositioning unit, the computer can return the patient positioningconstraints to the recorded positions. This system allows for rapidrepositioning of the patient to the position used during imaging anddevelopment of the treatment plan, which minimizes setup time of patientpositioning and maximizes time that the charged particle beam system 100is used for cancer treatment.

Patient Placement

Preferably, the patient 1430 is aligned in the proton beam path 269 in aprecise and accurate manner. Several placement systems are described.The patient placement systems are described using the laying positioningsystem, but are equally applicable to the semi-vertical and sittingpositioning systems.

In a first placement system, the patient is positioned in a knownlocation relative to the platform. For example, one or more of thepositioning constraints position the patient in a precise and/oraccurate location on the platform. Optionally, a placement constraintelement connected or replaceably connected to the platform is used toposition the patient on the platform. The placement constraintelement(s) is used to position any position of the patient, such as ahand, limb, head, or torso element.

In a second placement system, one or more positioning constraints orsupport element, such as the platform, is aligned versus an element inthe patient treatment room. Essentially a lock and key system isoptionally used, where a lock fits a key. The lock and key elementscombine to locate the patient relative to the proton beam path 269 interms of any of the x-, y-, and z-position, tilt, yaw, and roll.Essentially the lock is a first registration element and the key is asecond registration element fitting into, adjacent to, or with the firstregistration element to fix the patient location and/or a supportelement location relative to the proton beam path 269. Examples of aregistration element include any of a mechanical element, such as amechanical stop, and an electrical connection indicating relativeposition or contact.

In a third placement system, the imaging system, described supra, isused to determine where the patient is relative to the proton beam path269 or relative to an imaging marker placed in an support element orstructure holding the patient, such as in the platform. When using theimaging system, such as an X-ray imaging system, then the firstplacement system or positioning constraints minimize patient movementonce the imaging system determines location of the subject. Similarly,when using the imaging system, such as an X-ray imaging system, then thefirst placement system and/or second positioning system provide a crudeposition of the patient relative to the proton beam path 269 and theimaging system subsequently determines a fine position of the patientrelative to the proton beam path 269.

X-Ray Synchronization with Patient Respiration

In one embodiment, X-ray images are collected in synchronization withpatient respiration or breathing. The synchronization enhances X-rayimage clarity by removing position ambiguity due to the relativemovement of body constituents during a patient breathing cycle.

In a second embodiment, an X-ray system is orientated to provide X-rayimages of a patient in the same orientation as viewed by a protontherapy beam, is synchronized with patient breathing, is operable on apatient positioned for proton therapy, and does not interfere with aproton beam treatment path. Preferably, the synchronized system is usedin conjunction with a negative ion beam source, synchrotron, and/ortargeting method apparatus to provide an X-ray timed with patientbreathing and performed immediately prior to and/or concurrently withparticle beam therapy irradiation to ensure targeted and controlleddelivery of energy relative to a patient position resulting inefficient, precise, and/or accurate noninvasive, in-vivo treatment of asolid cancerous tumor with minimization of damage to surrounding healthytissue in a patient using the proton beam position verification system.

An X-ray delivery control algorithm is used to synchronize delivery ofthe X-rays to the patient 1430 within a given period of each breath,such as at the top or bottom of a breath when the subject is holdingtheir breath. For clarity of combined X-ray images, the patient ispreferably both accurately positioned and precisely aligned relative tothe X-ray beam path 2270. The X-ray delivery control algorithm ispreferably integrated with the breathing control module. Thus, the X-raydelivery control algorithm knows when the subject is breathing, where inthe breath cycle the subject is, and/or when the subject is holdingtheir breath. In this manner, the X-ray delivery control algorithmdelivers X-rays at a selected period of the breathing cycle. Accuracyand precision of patient alignment allow for (1) more accurate andprecise location of the tumor 1420 relative to other body constituentsand (2) more accurate and precise combination of X-rays in generation ofa 3-dimensional X-ray image of the patient 1430 and tumor 1420.

Referring now to FIG. 26, an example of generating an X-ray image 2600of the patient 1430 and tumor 1420 using the X-ray generation device2100 or 3-dimensional X-ray generation device 2100 as a known functionof time of the patient's breathing cycle is provided. In one embodiment,as a first step the main controller 110 instructs, monitors, and/or isinformed of patient positioning 2610. In a first example of patientpositioning 2610, an automated patient positioning system, under maincontroller 110 control, is used to align the patient 1430 relative tothe X-ray beam path 2270. In a second example of patient positioning,the main controller 110 is told via sensors or human input that thepatient 1430 is aligned. In a second step, patient breathing is thenmonitored 2620, as described infra. As a first example of respirationmonitoring, an X-ray is collected 2640 at a known point in the patientrespiration cycle. In a second example of respiration monitoring, thepatient's respiration cycle is first controlled in a third step ofcontrolling patient breathing 2630 and then as a fourth step an X-ray iscollected 2640 at a controlled point in the patient breathing cycle.Preferably, the cycle of patient positioning 2610, patient breathmonitoring 2620, patient breath control 2630, and collecting an X-ray2640 is repeated with different patient positions. For example, thepatient 1430 is rotated about an axis 1417 and X-rays are collected as afunction of the rotation. In a fifth step, a 3-dimensional X-ray image2650 is generated of the patient 1430, tumor 1420, and body constituentsabout the tumor using the collected X-ray images, such as with the3-dimensional X-ray generation device 2100, described supra. The patientbreath monitoring and control steps are further described, infra.

Patient Breathing Monitoring

Preferably, the patient's breathing pattern is monitored 2620. When asubject or patient 1430 is breathing many portions of the body move witheach breath. For example, when a subject breathes the lungs move as dorelative positions of organs within the body, such as the stomach,kidneys, liver, chest muscles, skin, heart, and lungs. Generally, mostor all parts of the torso move with each breath. Indeed, the inventorshave recognized that in addition to motion of the torso with eachbreath, various motion also exists in the head and limbs with eachbreath. Motion is to be considered in delivery of a proton dose to thebody as the protons are preferentially delivered to the tumor and not tosurrounding tissue. Motion thus results in an ambiguity in where thetumor resides relative to the beam path. To partially overcome thisconcern, protons are preferentially delivered at the same point in eachof a series of breathing cycles.

Initially a rhythmic pattern of breathing of a subject is determined2620. The cycle is observed or measured. For example, an X-ray beamoperator or proton beam operator can observe when a subject is breathingor is between breaths and can time the delivery of the protons to agiven period of each breath. Alternatively, the subject is told toinhale, exhale, and/or hold their breath and the protons are deliveredduring the commanded time period.

Preferably, one or more sensors are used to determine the breathingcycle of the individual. Two examples of a breath monitoring system areprovided: (1) a thermal monitoring system and (2) a force monitoringsystem.

A first example of the thermal breath monitoring system is provided. Inthe thermal breath monitoring system, a sensor is placed by the noseand/or mouth of the patient. As the jaw of the patient is optionallyconstrained, as described supra, the thermal breath monitoring system ispreferably placed by the patient's nose exhalation path. To avoid stericinterference of the thermal sensor system components with protontherapy, the thermal breath monitoring system is preferably used whentreating a tumor not located in the head or neck, such as a whentreating a tumor in the torso or limbs. In the thermal monitoringsystem, a first thermal resistor 2595 is used to monitor the patient'sbreathing cycle and/or location in the patient's breathing cycle.Preferably, the first thermal resistor 2595 is placed by the patient'snose, such that the patient exhaling through their nose onto the firstthermal resistor 2595 warms the first thermal resistor 2595 indicatingan exhale. Preferably, a second thermal resistor operates as anenvironmental temperature sensor. The second thermal resistor ispreferably placed out of the exhalation path of the patient but in thesame local room environment as the first thermal resistor 2595.Generated signal, such as current from the thermal resistors 2595, ispreferably converted to voltage and communicated with the maincontroller 110 or a sub-controller of the main controller. Preferably,the second thermal resistor is used to adjust for the environmentaltemperature fluctuation that is part of a signal of the first thermalresistor 2595, such as by calculating a difference between values of thethermal resistors 2595 to yield a more accurate reading of the patient'sbreathing cycle.

A second example of the force/pressure breath monitoring system isprovided. In the force breath monitoring system, a sensor is placed bythe torso. To avoid steric interference of the force sensor systemcomponents with proton therapy, the force breath monitoring system ispreferably used when treating a tumor located in the head, neck, orlimbs. In the force monitoring system, a belt or strap 2555 is placedaround an area of the patient's torso that expands and contracts witheach breath cycle of the patient. The belt 2555 is preferably tightabout the patient's chest and is flexible. A force meter 2557 isattached to the belt and senses the patients breathing pattern. Theforces applied to the force meter 2557 correlate with periods of thebreathing cycle. The signals from the force meter 2557 are preferablycommunicated with the main controller 110 or a sub-controller of themain controller.

Respiration Control

Referring now to FIG. 26, once the rhythmic pattern of the subject'srespiration or breathing is determined, a signal is optionally deliveredto the subject to more precisely control the breathing frequency 2630.For example, a display screen 2590 is placed in front of the subjectdirecting the subject when to hold their breath and when to breath.Typically, a respiration control module uses input from one or more ofthe breathing sensors. For example, the input is used to determine whenthe next breath exhale is to complete. At the bottom of the breath, thecontrol module displays a hold breath signal to the subject, such as ona monitor, via an oral signal, digitized and automatically generatedvoice command, or via a visual control signal. Preferably, a displaymonitor 2590 is positioned in front of the subject and the displaymonitor displays breathing commands to the subject. Typically, thesubject is directed to hold their breath for a short period of time,such as about ½, 1, 2, 3, 5, or 10 seconds. The period of time thebreath is held is preferably synchronized to the delivery time of theproton beam to the tumor, which is about ½, 1, 2, or 3 seconds. Whiledelivery of the protons at the bottom of the breath is preferred,protons are optionally delivered at any point in the breathing cycle,such as upon full inhalation. Delivery at the top of the breath or whenthe patient is directed to inhale deeply and hold their breath by therespiration control module is optionally performed as at the top of thebreath the chest cavity is largest and for some tumors the distancebetween the tumor and surrounding tissue is maximized or the surroundingtissue is rarefied as a result of the increased volume. Hence, protonshitting surrounding tissue is minimized. Optionally, the display screentells the subject when they are about to be asked to hold their breath,such as with a 3, 2, 1, second countdown so that the subject is aware ofthe task they are about to be asked to perform.

Proton Beam Therapy Synchronization with Respiration

A proton delivery control algorithm is used to synchronize delivery ofthe protons to the tumor within a given period of each breath, such asat the top or bottom of a breath when the subject is holding theirbreath. The proton delivery control algorithm is preferably integratedwith the respiration control module. Thus, the proton delivery controlalgorithm knows when the subject is breathing, where in the breath cyclethe subject is, and/or when the subject is holding their breath. Theproton delivery control algorithm controls when protons are injectedand/or inflected into the synchrotron, when an RF signal is applied toinduce an oscillation, as described supra, and when a DC voltage isapplied to extract protons from the synchrotron, as described supra.Typically, the proton delivery control algorithm initiates protoninflection and subsequent RF induced oscillation before the subject isdirected to hold their breath or before the identified period of thebreathing cycle selected for a proton delivery time. In this manner, theproton delivery control algorithm can deliver protons at a selectedperiod of the breathing cycle by simultaneously or nearly simultaneouslydelivering the high DC voltage to the second pair of plates, describedsupra, which results in extraction of the protons from the synchrotronand subsequent delivery to the subject at the selected time point. Sincethe period of acceleration of protons in the synchrotron is constant orknown for a desired energy level of the proton beam, the proton deliverycontrol algorithm is used to set an AC RF signal that matches thebreathing cycle or directed breathing cycle of the subject.

Although the invention has been described herein with reference tocertain preferred embodiments, one skilled in the art will readilyappreciate that other applications may be substituted for those setforth herein without departing from the spirit and scope of the presentinvention. Accordingly, the invention should only be limited by theClaims included below.

The invention claimed is:
 1. An apparatus for radiation therapy of atumor of a patient with charged particles from a charged particle cancertherapy system, comprising: a charged particle beam path, said chargedparticle beam path sequentially traversing: an injector, said injectorfurther comprising: an ion beam generation source; and a magneticmaterial centrally positioned within said ion beam generation source,said magnetic material creating a magnetic field barrier between a hightemperature plasma zone within said ion beam generation source and a lowtemperature plasma region, wherein a portion of said charged particlebeam path circumferentially surrounds (1) negative ions formed in saidlow temperature plasma region and (2) a negative ion beam resulting fromextraction of the negative ions from the low temperature plasma region;a synchrotron; and a beam transport system, wherein said synchrotroncomprises an extraction foil.
 2. The apparatus of claim 1, wherein thecharged particles run through said charged particle beam path duringoperation of said charged particle cancer therapy system.
 3. Theapparatus of claim 1, wherein said synchrotron further comprises: acenter; a pair of oscillation inducing blades spanning said chargedparticle beam path, said pair of oscillation blades comprising a firstdistance from said center of said synchrotron; a pair of extractionblades spanning said charged particle beam path, said pair of extractionblades comprising a second distance from said center of saidsynchrotron, said first distance greater than said second distance; anda deflector about said charged particle beam path.
 4. The apparatus ofclaim 1, further comprising: a statically positioned X-ray generationsource, said X-ray generation source located within about fortymillimeters of said charged particle beam path.
 5. The apparatus ofclaim 1, wherein said synchrotron further comprises: exactly fourturning sections, wherein each of said turning sections bends saidcharged particle beam path about ninety degrees.
 6. The apparatus ofclaim 1, wherein said synchrotron further comprises: four turningsections; and bending magnets, wherein each of said four turningsections comprises at least four of said bending magnets, wherein saidcharged particle beam path runs through each of said four turningsections.
 7. The apparatus of claim 1, wherein said synchrotroncomprises an equal number of turning sections and straight sections. 8.An apparatus for radiation therapy of a tumor of a patient with chargedparticles from a charged particle cancer therapy system, comprising: acharged particle beam path, said charged particle beam path sequentiallytraversing: an injector, a synchrotron; and a beam transport system,wherein said synchrotron comprises an extraction foil, wherein saidcharged particle beam path connects to: a carbon input foil in saidinjector; an aluminum output foil positioned (1) after said synchrotronand (2) across said charged particle beam, wherein said output foil hasa first side; and a beam position verification layer substantially incontact with said first side of said output foil, wherein saidverification layer comprises photon emitting centers.
 9. The apparatusof claim 1, further comprising: a first foil; a second foil; and a thirdfoil, wherein each of said first foil, said second foil, and said thirdfoil axially crosses said charged particle beam path.
 10. A method forradiation therapy of a tumor of a patient with treatment particles froma charged particle cancer therapy system, comprising sequential stepsof: generating the treatment particles in an injector; passing thetreatment particles through an input foil in said injector; maintaininga first vacuum in said charged particle beam path on a first side ofsaid input foil; maintaining a second vacuum within said chargedparticle beam path on a second side of said input foil, wherein a firstpressure of said first vacuum does not equal a second pressure of saidsecond vacuum; and injecting the treatment particles into a synchrotron,wherein circulation of the treatment particles in said synchrotronyields the circulating charged particles; accelerating circulatingcharged particles in said synchrotron yielding accelerated chargedparticles; inducing oscillation of the accelerated charged particlesyielding oscillating charged particles; extracting the oscillatingcharged particles from said synchrotron using an extraction foilyielding reduced energy charged particles; and transporting the reducedenergy charged particles to the tumor, wherein a charged particle beampath initiates in an injector, wherein said charged particle beam pathcircumferentially surrounds the charged particles in said synchrotron,wherein at least a portion of said charged particle beam pathcircumferentially surrounds at least a portion of all of: (1) thecharged particles; (2) the accelerated charged particles; (3) theoscillating charged particles; and (4) the reduced energy chargedparticles.
 11. A method for radiation therapy of a tumor of a patientwith treatment particles from a charged particle cancer therapy system,comprising four sequential steps of: accelerating circulating chargedparticles in a synchrotron yielding accelerated charged particles;inducing oscillation of the accelerated charged particles yieldingoscillating charged particles; extracting the oscillating chargedparticles from said synchrotron using an extraction foil yieldingreduced energy charged particles; and transporting the reduced energycharged particles to the tumor, wherein a charged particle beam pathinitiates in an injector, wherein said charged particle beam pathcircumferentially surrounds the charged particles in said synchrotron,wherein at least a portion of said charged particle beam pathcircumferentially surrounds at least a portion of all of: (1) thecharged particles; (2) the accelerated charged particles; (3) theoscillating charged particles; and (4) the reduced energy chargedparticles; and further comprising the step of: generating X-rays with anX-ray generation source located within about forty millimeters of saidcharged particle beam path, wherein said X-ray source maintains a singlestatic position: (1) during use of said X-ray source and (2) duringtumor treatment with the charged particle beam, wherein, for a distance,the X-rays emitted from said X-ray source run substantially in parallelwith the charged particles.
 12. The method of claim 10, furthercomprising the steps of: extracting the reduced energy charged particlesfrom said synchrotron; and controlling an intensity of the reducedenergy charged particles, wherein said step of controlling saidintensity occurs prior to the charged particles passing through aLamberson extraction magnet in said synchrotron.
 13. The method of claim10, further comprising the steps of: rotating a rotatable platform to atleast five irradiation positions covering at least ninety degrees ofrotation; and irradiating the tumor with the reduced energy chargedparticles during each of said at least five irradiation positions, saidrotatable platform configured to rotate the tumor.
 14. The method ofclaim 10, further comprising the steps of: generating an ion beam in anion beam generation source of said injector; creating a magnetic fieldbarrier between a high temperature plasma zone within said ion beamgeneration source and a low temperature plasma region using a magneticmaterial centrally positioned within said ion beam generation source,wherein said charged particle beam path initiates with negative ionsformed in said low temperature plasma region; and extracting thenegative ions from said low temperature plasma region forming a negativeion beam, wherein a length of said charged particle beam pathcircumferentially surrounds said negative ion beam.
 15. The method ofclaim 10, further comprising the step of: forming a vacuum barrier withan output foil between atmosphere and a first portion of said chargedparticle beam path within said synchrotron, wherein said output foilcomprises a first surface, wherein a coating substantially covers atleast a portion of said first surface of said output foil, said coatingconfigured to emit photons when struck by the reduced energy chargedparticles, and wherein said extraction foil comprises a thickness ofless than about one hundred micrometers.
 16. The method of claim 10,wherein said extraction foil consists essentially of atoms having six orfewer protons per atom.
 17. The method of claim 10, further comprisingthe step of: generating X-rays with a statically positioned X-raygeneration source, said X-ray generation source located within aboutforty millimeters of said charged particle beam path.
 18. The method ofclaim 10, further comprising the step of: rotating a rotatable platformunder a distal end of said charged particle beam path, wherein saidrotatable platform rotates around an axis aligned with gravity duringuse; and controlling the treatment particles exiting said synchrotron interms of all of: timing, extraction energy, and extraction intensity.